I agree, do not get the SNA ... last month over thanksgiving week, I went to a Beach Front Marriott in Phuket. I applied all my SNA for either a Beach front cabana or a 1 bedroom suite with pool access. 5 days before arrival, I got an email rejecting my upgrade and saying I can not use them anymore as the hotel will not give me one of those rooms. Long Story short, I get to the hotel with my SO and the checking agent tells me I have been upgraded for being Platinum to a 1 bedroom suite with pool access!!! Yes, I still have the SNA and now they are going to expire as they upgraded me via status and not via SNAs. Last Marriott visit is on points (300,000) for 7 nights over new years at the Marriott Maui Wailea, so can't use the suite night upgrades.

BTW, the extra space was wonderful and having two bathrooms was even better