Problem is, scrolls serve two purposes. They makes wizard's spellbook, and they make up for not having a divine or arcane caster. Just like how everyone can try to pick locks.
Why does anything need to 'make up' for not having a spellcaster? Spellcasters are in no way needed to beat the game. If I play with four spellcasters, they get nothing to 'make up' for the fact that I don't have warriors in the party. Warriors who in BG3 get to beat the snot out of everything while enemies drop your squishy casters.
As for the double purpose - scrolls are meant to be a backup for
spellcasters when they run out of spell slots. Spell scrolls are not for non-spellcasters to become spellcasters. That's a Larian invention and it's not a good one.
