i think the idea is just not to get hit.
Think of it this way, if you were boss at melee with Pichu and could avoid getting at all time.
Would using electric attacks effect your game?
I think Pichu is more about defensive aggression, and mind-games.
Always leading but never attacking until
A - The enemy attacks which makes openings
B - Finding a weak point in they're plan/skill
Pichu like Pikachu play very similar to Captain Falcon with they're falling speed, and long distances jumps. The aerial attacks of these characters seem more for positioning your enemy for the kill other then making the kill.
Here in this video -
http://www.youtube.com/watch?v=SGTWI2f6AIE&feature=player_detailpage#t=48s
You see this fight against captain falcon in where pikachu use his N-air to pass through the top of his shield adding a bit of shield pressure, but staying just high enough, and fast enough to pass through the sheild without getting caught.
Each these character have good air momentum capture that lets they're attacks pass through the enemy after a dash jump so that they're aerial attacks aren't as punishable for missing, or hitting.
Look a this video -
http://www.youtube.com/watch?v=4Y8rQ_0zNIg&feature=player_detailpage#t=98s
in this combo against jiggy puff when captain falcon misses his sweet spot for his knee, it positioned jiggy puff for another knee which he sweet spots for the kill.
This also works for Pichu's N-air, if you don't sweet spot pichu n-air it can lead into another N-air which you can sweet spot for the kill.
Now if you take all this into account, prefect agility adds for great approaches, mind games, and escapes. Since pichu's jumps aren't very far you have to the reach down between you, and you enemy's attack.
I'm sill trying to figure out more ideas, and uses for pichu other aerial attacks, that does do damage to himself, i'll find them im sure.
Another thing is, though i'm sure most do this already but just an case. Use D-tilt for in place of dash attack, the dash attack reach is very poor, and is only good for stopping large hit boxes like Samus Fully Charged Shot.
But the most important thing is not to get hit, period. I know it sounds impossible but pichu is like the only only that might be able to pull this off, he's small for a reason.
Also another trick that i thought of watching a falco video. Agility Stall.
Agility Stall is just like Falco's Forward-B stall, but a lot more harder to pull off but possible. Which you do is let go the ledge by tapping back away from the stage, and immediately hit up-b, and press forward. It might take a bit to get use to, and i haven't tested it against anyone yet.
I was playing around with pichu, and found that you can agility into a ledge grab as long a your facing the ledge, and that your aren't holding up or down on the control stick. Good to know for escapes say like jump backwards off the ledge, and using Agility straight down at it.