Honestly, I do not expect to get an upgrade to a suite. I have so far experienced everything from the room I have booked to an upgrae to Junior Suite, the later at Crowne Plaza and Indigo Hotels. And it say "Upgrade up to ..." which gives the hotel some flexibility and of course it reads nicer to the customer. Sometimes, I book a higher room category and hope for something nicer, but my expectations are in so far low. If the hotel has only one or two suites, I would not expect to be upgraded into a suite. If I want a specific room, I simply book it.

It is different at InterContinental Hotels, where I rely on my Ambassador Status, which gets one category upgrade. And my expectations are here low as well.
In geneal, I helps to keep the expectations low. It also helps, if you are loyal to a certain hotel over the time in regard to upgrades. .

By the way, similar to Hilton, where my Diamond Status get me Lounge access - if available - and usually a nicer room, but not always.