I'd suggest asking the seller what will happen after you buy. Ask them to explain the process. If you have further questions, you can follow up. You have a big advantage over many renters because you know about the process already.
Here is the ebay money-back guarantee page. I see nothing eliminating hotel reservations.
eBay Money Back Guarantee covers most transactions on eBay. It means buyers can get their money back if an item didn't arrive, is faulty or damaged, or doesn't match the listing.
www.ebay.com
In the end, you are going to have to be at least somewhat confident about your purchase.
Almost 20 years ago, I vividly remember buying my first timeshare rental on ebay. $400 for four nights at Old Key West at Disney. Was I nervous? Absolutely! It was quite the feeling of relief when they said "Welcome Home." when we arrived.
Then it felt like we were cheating somehow for getting such a deal. Taxes were even included.
Anyway, If it all went sideways, there were plenty of places in Orlando to stay and we only lived 3 hours away, but it was foreign territory. We went on to rent dozens of various timeshares before finally buying.
Renting timeshares from various places can save you a ton of money, but it isn't for everyone. Many people have looked at me like I am insane when I said I booked vacation rentals on ebay, Redweek, etc.
Good luck!