The OP has asked a good question, welcome to Flyertalk and congratulations on obtaining Platinum status.

Are you now going to reap the rewards of your loyalty ?

Well actually hotels have no obligation to upgrade you to a more expensive room. The terms and condidtion are carefully worded, allowing hotels to provide an "upgrade" to a room priced exactly the same as the one booked.

Quoted from PC Website:
Hotel Room Upgrades for Platinum Members: Platinum level members will be offered a complimentary upgrade, as determined by the hotel, which might include rooms on higher floors, corner rooms, newly renovated rooms, or rooms with preferred views.

I have previously been upgraded to a standard room with a carpark view, and had the above terms and conditions quoted to me by smiling reception staff.

In 11-12 years of platinum membership my tally of complimentary breakfasts in Holiday Inn's and Crowne Plaza's is nil.