Cuation-I’m surely an idiot on cosmology and physics. Current theory is that all mass energy will eventually wind up in black holes - which will then evaporate

Cuation-I’m surely an idiot on cosmology and physics. Current theory is that all mass energy will eventually wind up in black holes - which will then evaporate. All mass energy will then be maximally dispersed in the entropy death of the universe. I think that means the Casimir effect is not destroying mass energy, just dispersing it to a useless state.