>>96086057
if you have mtg experience, this question is the equivalent to asking:
"why isn't summoning sickness permanent?"

the answer is that the card would never be usable.
the reason it is temporary is to give the other player a chance to respond to what is a powerful card/play

austism (mtg summoning sickness) does not apply to normally played cards (more like yugioh) because their impact is much more limited compared to the high stat highly synergistic composite cards (created through frenning)