As a regular flyer in cattle class, I love the benefits of a gold or silver card. No, I don't feel more important, but boy do I feel less hassled. Try checking in as an economy passenger in some sub-Saharan airports and then see the difference when you can get into the business line. You can save hours standing in long, hot sweaty queues that way. Lounge access is nice, too - especially when you have a long wait for a connection home after an overnight flight into FRA or AMS.
Most of the time I have to take the cheapest flight available and I tend to have about 20K miles on three or four cards at the end of the year, not enough to get a silver card - but it's nice when I get there. In all the years I've flown I've only been upgraded to business class twice. Once was LHR to Paris, so it wasn't much of a benefit anyway, the other was from Addis to FRA - and that was nice.
I'll take the free flights too. Mrs G has to make a number of trips to Madagascar over the next few years and I'll join her on a couple of them curtesy of my Air France miles.