Why does GTO-wizard like small sizing?

it's trying to make OOP as indifferent as possible with as much of their range as possible

Betting small is a cheap price to fold out unconnected junk that still has equity to hit whilst also maximising thin value with hands that are ahead vs draws and stubborn pairs that will mostly whiff. Whereas betting larger does neither and forces OOP to defend with a stronger range, whilst reducing how often we can bet and win with ass like T2s.