Of course they’re not using it to commute daily. You even pointed out in your first sentence: It’s a hobby.
Someone else in this thread also mentions that many small aircraft have multiple “owners” who share it. Just like timeshare vacation property. Everyone who is part in it, shares the cost of maintenance. This makes it even cheaper. This counters your statement of:
that’s not saving you any money, it’s likely costing you significantly more in storage fees, etc.