Note you get more rewards per night the further you get into the promo. Starts at 1k per night for the first increment, then 2k, all the way up to 5k per night (for nights 21-25). Category 1 Hyatt properties are 5k per night, Cat 2 at 8k, so it's an awesome deal if you get that deep.
Points and Cash nights count as an eligible stay. Points only do not count.
Points and Cash works great, because you will get many of the points you spent back in your account.
Hyatt Points And Cash Pricing By Category on Hyatt's Website
Search Hyatt Properties By Category And Location
If you are not a Hyatt Platinum Member and are on Basic Status Level, you will get Platinum after 5 stays or 15 nights.