I don't think we're in KansasBrinstar anymore, Kraid.
Well, because we're talking about how it could approach to character development. Ridley's size, stance, weight, body composition, etc plays a huge role in how he plays and how he would be balanced, just like every other character (it isn't just a Ridley thing
Silly Ridley haters). By discussing it we are mentioning possible ways it could work, which means that this would effect how Ridley as a character would work.
If say Ridley is crawling, he could more easily "push himself" up into the air (kinda like Charizard's Down B in Project M), and thus, make his ground attacks moreso about going into the air than if he was a standing character, and would make everything about being in the air. If Ridley stands on two feet, then he could be a character with balance between the two (which to me sounds very stale, as we as an unfitting way for Ridley to work).
However, I think the former is more interesting, unique, and fitting, and really would make Ridley not just work better, but stand out and be totally different than anyone else in smash. We've had characters who are heavily reliant on the air, but none that quite work with their ground game like that. Plus, if this is indeed Ridley's playstyle, it could mean he could lead into some cool air combos, and even spikes (I imagine his down air would be a downward claw/tail smack spike of cunning death).