I don't think the OP has Marriott status, so lounges won't matter.

Also, I have the impression that OP plans to spend free night certs as soon as they are earned. It doesn't work this way. It takes time for the stays to post and for you to receive the certs. Also, usually you must make a reservation in advance and specifically associate the reservation with your free night cert. The hotel might not have the right availability at the last minute.