Yeah, that too... my surface mushrooms tend to be flat and blocky because I don't feel like randomly hammering blocks, lol. That, and if you have one layer of mud and you stick mushroom grass on that, it creates this annoying gap between it and the dirt underneath... unless you do 2 blocks thick of mud which is yet more work I usually don't feel like doing...The biggest thing this'll do (other than let you change the look of your base/chests ofc) is that it'll make it a lot easier to create a surface mushroom biome without destroying the natural look of the terrain.
This will help so much with that.
EDIT: Also, making tiny jungle biome for a jungle fishing hole, etc. Same thing, it's a lot less work than having to manually remove and replace blocks lol.