There is also variety of playstyle ...
With Heavy Crossbow, you want to make every shot count ... bcs you dont get another chance in your turn (unless you have feat, but there we go in matter of corelation between gain and cost.
Wich is actually not bad for Rogue, bcs you dont get Extra attack anyway ... your Sneak Attack get stronger instead ...
Meaning Rogue with Heavy Crossbow play for single big number ... with potential risk of loosing the only attack they have and do nothing.
With Bow, you have two attacks (and more on higher levels ... not sure if BG-3 gets high enough tho).
So what you get is potentialy even biger number, with option to divide that number on two targets.
Not so good for Rogues, since they still dont have Extra Attack, still can shoot only once ... but good enough for Fighters who can be more deadly now.
> If crossbow can shoot twice, why bother with bow? You only loose up to 2 points of damage per attack, there is no benefit ... ergo no point.
Then there are Hand Crossbow ... weak, but can dual wield ... meaning your Rogue can attack twice ...
And therefore have double chance to apply Sneak Attack.
Quadruple with Larian rules.

If offhand will be capable of dealing it.