EGS actually has an excuse for this nonsense, what with magic "having a flair for the dramatic". Of course speed would be boosted with cat forms! It's appropriate!
Granted, Uryuom based transformations don't seem to buy in to "flair for the dramatic" logic so much, but it's still a sort of magic that's also alien technology. I'm sure there's some logic that works there, too, for super obvious reasons that are obvious and logical to all.