It was an impulsive decision at the time. He wanted to run a tavern.

[It's hard to tell, but running a hand over the crystal will reveal it's been chipped. Probably an indication it's use has been worn. As Kazuma walks passed him to check some of the other appliances, they too will have crystals attached to them. Most are cracked, but there are a few that seems to still be in intact, just not functioning.]

Cinderella, Sleeping Beauty, you know a story, it probably exists there. They are reality in that world, and our purpose for being there was to help restore them.