>Why should Larian waste resources on that?

I think it's the same reason they do everything the way they do it. Because it is their "style/feature/flavor". They want their games to be recognizable as Larian's at first glance more than they want the game to be better. Probably a small indie studio becoming big and recognizable thing.
Imo this partucular feature is actually restrictivend and overall bad. But since DoS 2 was a success they'll copy as much as possibly from it.