I'm a bit surprised that they chose this area for a Waldorf Astoria. There are much better locations for a better beach running from Playa Mujeres to Tulum.
This particular area of Puerto Morelos can be plagued with seaweed. Also, the ocean water can be murky most/some of the time. I stayed a few years ago at the Hideaway at the Royalton Riviera Cancun which is right down the beach. I knew what I was getting into regarding the beach as I did my heavy research beforehand and yeah, it was all true.
I definitely wanted to try this hotel out, but since I'm an absolute beach lover, I'm leaning towards the Conrad Tulum instead.