I was a stamp collector in my younger years, getting started as a Boy Scout in the 1940's. I had lots of plate-blocks, and quite a number of full sheets going back to the days of 3 Cent 1st class stamps. They never appreciated in value, and I began using them for postage about 10 years ago... now all gone.

I also have lots of First Day Covers with cachets that I dutifully ordered each time a stamp was issued. Again, they are a drug on the market today and you can't give them away, even though they are pretty, and the events honored on the stamp do help you learn some US history. Below is an example from a current eBay auction honoring Volunteer Firemen in 1948.

Collectors of today's casino chips that are issued to commemorate something, take note... nice to collect, but will not appreciate and unlike postage stamps, they will likely be demonetized and you won't even be able to play a game with them at the casino.