I am a mere Gold member and have never had any higher status, so I don't have anything to compare against. However, I certainly wouldn't say it's a "waste of time". I've received room upgrades ~50% of the time - sometimes it's just a higher floor (who cares) but sometimes it's larger or nicer room. In my last stay at a Residence Inn in downtown Toronto, I was upgraded from a studio to a 1 bedroom suite. I would consider that a substantial upgrade.

I'm sure it depends on the market, time of year, etc. But the benefits are not "nothing". They're just less than higher tiers.