Usually, when you book online, it tells you what type of room to expect: for example, garden view, city view, etc. Normally, if a hotel offers "upgraded" free nights, they want extra $ per night or extra points.

The awards without any additional costs or certs is their most basic room.

For gold/plats, they usually upgrade you to the nicest available non-suite room available. Key word is available.

Silvers may get upgrades, but I would not count on it.

Billy