Beat case scenario: your grave sits unlooked at 99.9% of the time and wastes space. In a couple hundred years some douchebag archeologist who wants to pretend they aren’t a grave robber will fuck with your shit in the name of “science”.
Setup a shrine for your loved ones in your house if you have to. The world is for the living. When I die toss me in the nearest dumpster.
Inhumation has been practiced for hundreds of thousands of years. It’s about as basic to human existence as fire, pottery, and agriculture, if not more. Inhumation will cease exactly when there is one human person left on earth, and this unpopular opinion will be dead and buried long before that.