I heard of the claim that in tabletop Bard gets this advantage also on pure Ability Score rolls, i.e. if you roll against Wisdom etc. That would indeed be strong.
Aye, in TT (Also, RAW) it is applied to all ABILITY rolls you don't have a proficiency bonus on.
Meaning, not only skills, but also things like Initiative (Which is a Dex ability roll), Counterspell (Charisma ability roll), Concentration (Con ability roll) and direct ability skill checks.
Which is pretty nifty.
In BG3 though, it's just a slight boost to the skills you haven't put proficiency in (Most likely non-Dex/Chr skills like Perception and Insight). Which can make a difference, but will largely be overshadowed by party members that actually have the stats for these skills (Such as having a Cleric/Druid with Perception proficiency finding all the traps for you)