That sounds highly reasonable as well. Asterion finally getting his long awaited rest (even though he does enjoy his vision of the hotel). Only drawback I could see with him and the MC living on in Hades, is the hotel would more than likely cease to exist after Asterion passes from the living realm. I'm under the assumption it's existence is tied to him perpetually.
Viewing post in Thoughts on possible immortality for MC (Semi-Spoiler)
maybe not, the labyrinth was created to hold many more children of poseidon as prisoners, but athena got foiled on that. also the realm stays there even when asterion moves away in some of the ruthless endings. the question is if the hotel can be kept running if the realm doesn't have a master, or if there can be a master if there are no prisoners.
however, considering hermes request, it's quite possible you might destroy the realm inadvertly. but it could be just one of many endings there will be.