Yes. I see quite a few three letter accounts advocating for burning plastic. Let them throw some in their fireplace of the chimnea while relaxing with the family and see how that goes.
On the topic of food waste, my time in the kitchen says most foods will burn just fine. Although, they often leave residues that I could see being problematic when they build up.
As with everything, you'd need specifics to determine the right tradeoffs. It would seem to me there's potential in reducing the transport distance and land use of solid waste, and also reducing extraction, transport, and burning of some fossil fuels, if a burn the trash for electricity program works. But specifics matter, of course.
A fireplace is a smoky thing, without enough air (even the wood makes a lot of smoke). An incinerator makes sure to supply enough air.