Yes, use the certificates for an expensive property if possible. Are you traveling anywhere in the US that has a Park Hyatt? I would want to get at least $400/night value out of thise certificates.
The annual retention night is limited to category 1-4, so that can make sense to use somewhere cheap if you do not have any better options.
But, if you really won't be able to use them anywhere else, then of course using the certs anywhere is better than letting them expire...