But it has each of those things. It sacrifices depth of gameplay that those specialised games have in their specialist areas, to include a wider variety of things to do.
Does it really though?
Sure it has rpg mechanics and an overworld, but so do a lot of anime porn games, and people still only play those for one reason.
My point is that while bannerlord has elements from different genres, the battles are at the centre of it all, and if you removed them the game would be a laughable shell of nothing, like a p2w mobile game.
Something like fallout 4 is a jack of all trades because it has about 3 different core mechanics it pushes you to using (shooting, base building and looting/exploration), but if you removed any of them the game would still be intact. On the other hand the new God of War games have a lot of very basic puzzles in them that wouldn't stand up on their own, but exist to give breaks to the combat which is what the game is really about.
Its not a jack of all trades just because it has token elements from different genres.