I think sneaking is very useful in BG3. In one of my favourite fights, you can sneak up to the roof beams to a perfect sniping spot - or shoot down a chandelier to set your enemies ablaze.
For one of my characters, I have made my own very risky side quest "steal from the Zhentarim (whenever possible), and give to the poor (the Tieflings)" 😄 (Yes, this would be the fantasy equivalent to stealing from the mafia, i.e. maybe not the best and most healthy idea. But so far, my Tavs made it out alive ).
In the former Selûne temple, you can sneak into the Zhentarim's storage room from an adjacent room, and sneakily steal everything from under their noses. And then sneaking back, and innocently buying some healing potions from Rhoa Moonglow, the Zhent - with her own money 😄
I have had a harder time getting Arcane Trickster to be as effective, although maybe at higher levels it is.
One thing I really like about the Arcane Trickster is the Disguise Self spell. You can avoid some fights simply by using a fitting disguise, and tricking your way in.
