The game being very casual...flippant even with player/party member death is another thing. Like there are more consequences to getting Volo's surgery then there are gettign your brain *eaten* by the mindflayer in the crashed ship. Hell, asterion will even tease you about him accidentally killing you the next day, and Gale has lines basically amounting to 'boy, the Fugue plane sure is dreary'.

And of course we even have a certain hard-to-ignore skeleton chilling in camp who provides resurrection for bargain basement prices.

Other games (including D&D games) treat readily available resurrection magic (or even just bringing back KO'd characters at 1hp at the end of fights) more as a gameplay/narrative break that's necessary for play, but not narratively acknowledged. They also typically give you a game over if the main character is killed off (if there isn't a revive at 1hp at combat end mechanic) for narrative purposes.

BG III treats death narratively as an inconvenience. Something you have a chuckle with your friends over later. It also has a loose definition of 'main character', with the player's avatar's main distinguishing feature being that they are the default conversationalist/centerpiece of cinematics and cutscenes. Combine these, and the significance of the player avatar as the 'protagonist' of the story feels rather lacking, IMO. Particularly if you are rolling a custom character, since you don't really get anything in the story that's unique and created specifically for your character that Origins don't get.