Is hard to airdodge down quickly out of the 2nd shine (westballz double shines right?) so no, is not that easy and you'll probably get punished if you don't do it fast enough, not that is useless, I think is just a mixup that might come in handy for pressure.
But then again, pressure not only involves shining the crap out of your opponent's shield, but well spaced attacks and your overall laser game also puts pressure on your opponent. The whole idea is to force the enemy to remain in a deffensive position, always shielding, rolling, spot dodging, jumping away and whatnot, so that you can overwhelm them (provided you have enough techskill to do so) offensively with your attacks and get a combo or edgeguard setup. At the end of the day is up to you to react quickly enough and punish.
I personally don't like westballz falco style, he's too reckless and often times is very predictable and gets punished very hard. In my opinion, is not worth trying to use his technique unless you're planning to work really hard on it and perfect it.
I think most novice falcos should focus on effective and simple things like spacing your attacks, you can do a retreating nair after hitting a shield with your shine and if your spacing is good enough they can't grab you, or you can just dash dance next to them shielding and poke their shield cause it gets too small.
Learning to read your opponent's actions is significantly more valuable than learning tech skill.