There is no problem in modelling objects like that.
Games have been doing that a lot, and when you see a landscape scene, all those trees, vegetations, house etc… are usually not part of the same geometry, but different objects sticking together.
And in the end when you have a complex model, it can save a lot of triangles in the face count, by example this very simple object if everything is the same geometry :
And if it’s not same geometry :
18 triangles saved, but that’s a very simple object, now let’s imagine there are much more buttons/etc… on that object, there are a lot of object similar in the scene, + the land + every trees, rocks, houses etc… and you can see in the end how a scene can benefit in polycount from not everything being the same geometry
After that there are the texture/normal/bump map that can be used to make believe something is complex while it has very few poly :