It sucks in: people & zombies (+any other NPC's),cadavers,props,weapons etc. There should be "intensity" levels
Int. 1: vaccume items which you hold the vaccum at
Int. 2:select individual items which then After pressing trigger all get vaccumed (for more niche scenarios)
Int. 3: vaccume EVERYTHING you've placed
It could be used to clean up the playspace After you've finished with your Business.
Many games have a "delete" Tool (for example garry's mod),and I believe a vaccum cleaner could fit into this category quite well. Also i find it comical