Cost to cure. Athough if it has access to the outside driveway, it might make a good RV parking space. Maybe a rehearsal room for a band? Movie theater? Bomb shelter? Private aerobic studio or home gym? DUNGEON!! Bioweapons lab. Grow room. How about a home detention center for the teenager of the house?
Actually, you could probably mezzanine it (maybe 3 floors) for a great home office or "extra apartment".
Racquetball court.......aaahhh yes, I remember now.........
I did one a little over a year ago, needed a 4 wheel drive vehicle to get in, large log cabin, 5-10 acres, in the middle of the mountains. I couldn't believe it when he showed me the full regulation size raquetball court. The best I could do was to find a couple of properties within 40-50 miles with large shop buildings.