It's in his stomach, so yes, you have to kill him.

This is clearly OP. That it considered an uncommon wonderous item in 5e TT does not change that fact. You also fail to consider that unlike the tabletop, the BG3 player is GUARANTEED getting this at an early level. This allows for metagaming exploits such as Wizards using intelligence as a dump stat (8 int). In terms of point buy in the character generator, this is worth 9 extra points.

2/2 Point buy:
* 9 extra point just to get from 8/9 to 15/16.

I tried that and for now I'm really struggling to hit anything .. how does it work for you ?

same here, started with shield dwarf wizard, 8 int , 16 str, 16 con, medium armor, battle-axe wielding warmaiden having a blast

could even knock down con to 14 and pump some points into dex

While that would be a tactic to use, it feels so incredibly cheap to me that I'd never do it, but to each his own. Having this bump up your wizard from 16 to 18 is still very useful. Can also use it on a Eldritch Knight or Arcane Trickster to get their stats up.