A hotel is paid by Marriott when a guest redeems points, certificates, nightly upgrade awards and so on. The redemption occurs at check in... so, in cases of a no show, the redemption doesn't happen and the hotel is left out of pocket. You can sometimes get lucky and the hotel will be sympathetic to your situation, so you should certainly reach out to the hotel and plead for mercy, however, they are within their rights to charge you.

The logic behind this isn't completely unreasonable but it does feel most punitive when you've booked a very short stay. If you book a cash stay of 7 nights, and then do not show up, the hotel will cancel your booking and charge you a cancellation fee equal to the first night. If your stay is $685 x 7 = $4,795 a penalty of $685 doesn't feel too unreasonable. Likewise, if you booked a 7 night stay using points, and didn't show up, the penalty would also be $685 and you would receive all of your points back, which also doesn't feel too punitive (as your points are likely valued at many thousands of dollars). However, if you book a one night stay, whether with a certificate, points or cash, the penalty for a no show will feel punitive, because it's equal to the maximum you would have spent had you actually shown up...

A painful and unfortunate situation for the guest, but hard to imagine how the policy could be any different, because the no show penalty (and cancellation after deadline fee) being expensive is by design to discourage no shows.