i am with you that in some project we don't need to make every thimg in wall type but at normal it reaaly effect exactly in the point that was in this comment
(
1.If the client ask you the Brick quantity in volume(cubic meter) you cannot able to take from that model.
(Most of the time they will ask area only. so that case we can take from Material take-off)
2.While doing Block work GA shop drawing if you wish to turn of the finish layer, you Can't.
3.It will Increase the types of wall because of the different finishes. and its confusing also.
4.The Block wall starts from the structural slab but wall finishes starts from floor finishes. So you cannot able to make like that in Multilayered.
)
so i think for me it better really to use every layer in type wall ( brike in a wall type and finish with sand and mortar in wall type )
in skitrting i think now it also better to use type wall but i don't now because i will need to have it quantatity permetre not square metre