In dnd almost all familiars can't attack(except for imps and quasits), but they have usage in combat - they can perform "help" action on an enemy to impose an advantage on your next attack. That is very neat - conjured imp can turn invisible, sneak on an enemy, then "help" and invisibility never breaks because imp didn't attack - a great strategy to gain an advantage.
In BG3 this isn't a thing as familiars don't even have "help" actions - Larian, please fix that
