As a platinum, you should definitely never expect for a suite. As mentioned before, it's not part of the T&Cs and Platinum isn't Hyatt's top status. Diamonds should also never expect suites but many have good experiences with hotels offering them anyways.

As a platinum, the best benefits that you can expect are 15% extra points, higher speed internet, and the chance for 2 pm late checkout. Other than that, it's nothing special.

Also kudos to the member above that has gotten 3-4 suite upgrades as a platinum. You probably have one of the best ratios.