Ever read or watched Fullmetal Alchemist? I'd say it's sort of the same thing the brothers did with their house. No returning there and taking it easy with the task at hand not completed yet if there's no home to return to. In this case, also a funeral pyre for the teacher he thought was dead. Also, the house would've just fallen to a state of disrepair if nobody waltzed in and took it over or something too, y'know? So this also prevents squatters and whatever else might come upon the place from desecrating the place with his memories of his master.