I said to myself I would not reply, but my goal is to help people so I will try and help you but it is down to you whether you take or leave the advise.
Walking is core fundamental that gives ANY character multiple options as long as they use it correctly, it is hard to use walking incorrectly.
Why do I speak of walking so much?
Closes distance between yourself and your opponent.
(This is without having the delay of shielding, jabbing, and actually having all options available to you that fox trotting and dashing take away whilst you are in these animations.)
In Luigi's case, walking whilst throwing periodic sensible fireballs means he gains notable stage presence .
Whereas when dashing you commit even more, you can no longer be ready to perfect shield (As efficiently, it's not impossible to perfect shield after a dash but you make the job harder for no good read other than wanting to close space quicker) incoming projectiles because you are about to be hit.
Like I have said before and multiple have told you, walking everywhere is NOT what I am suggesting or attempting to say you should do.
I will stress that walking has multiple uses both defensively and offensively.
A visual demonstration of what I talk about can be noted here
https://www.youtube.com/watch?v=3ekwB3c6CRg - 20:56
I am re-watching this match myself and I can say I achieve almost nothing by dashing and then shielding...I've already provided Static the opportunity to punish me multiple times in game 1.
Game 2 you will more of what I am speaking of and have it mentioned to you as well. I can definitely be walking even more to gain positional stage control whilst maintaining the ability to attack but my game-play is not as refined as it is now.
I asked you question in my previous statement.
How do you approach?
Luigi's approaches are really not that strong, but there are powerful because what they can condition an opponent to do.
SH fair (Good, but an opponent not ignorant of the fact this is will punish it which is why it needs to be used in moderation)
Cyclone ( A go to option for a number of Luigi players, one that I will really only go to when I have either not used it enough or it's arguably only one of the other choices I have left.)
I say that because although the multiple hit boxes are good, as an approach option it is highly punishable as long as the opponent respects the option, to get a maximum of 9% and MAYBE some positional advantage if you do get the final hit of cyclone is not worth the ending lag being severely punished by a smash attack or possibly being set up for a gimp because you are about to be thrown.
Cyclone can also be teched whilst Luigi is still spinning if you do not rise accordingly so it's something I don't see heavily considered enough, I'm not saying you said otherwise I am just saying what I see in general and explaining why it can cause anyone problems.
SH D-air - One of our better options, auto cancels, throws out a hitbox that is not too heavily committed and we are ready to jab. grab or do whatever we want as we land but not too much horizontal distance covered.
Fireball - Best projectile we have ever had. 6%, travels a decent amount of distance and maintains the damage the only setback is the hit-stun is actually minimal but not everyone exploits this so as an approach option mixed with walking you can see what your opponent does in response to you throwing periodic fireballs and grab/dash grab dependent on spacing if you see shielding patterns too often. Use aerials accordingly if they choose jump, jab if they do close the distance on the ground.
Walking and dashing you have these options... though having to cancel out of a dash you are progressively giving yourself more opportunities to get punished and high level players will use this against you.
I have already gone on a tangent with some of this but I hope even if you do not see what I am saying right now you will come to see it in due time.
On another note, I do agree with you on this point you made.
It should not matter how good a player is to have a debate with them...though you do need to be able to logically debate with anyone.
The reasons why I can say your reasoning was weak is because the opponent can see what you are doing when you dash at them as well. (To be able to jab from a dashing state you have to let the animation finish press too early gets you a dash attack)
You commit more, have even less options, unless your dashing with the intent on punishing which not all dash attempts in general are about punishing but showcasing frustration or just wanting to close distance quicker.
Through walking in moderation, you keep all or your options open and with Luigi you have some of the best buttons and grab damage conversions this game has to offer unless you have predictable patterns the opponent can only account for what you next intend to do from a walk because you have every option available to you including dash attack (smack the d-pad left or right, hit down on the c-stick and you get dash attack.
Keep this for future reference, although I did reference this earlier I was not as in-depth as I am being now so if you do not see my point even after all of this then fair enough.
I can say I tried and for those who understand neutral game and wanting to have stage control and all options available more often than not will see what I am attempting to get across.