I think you should review the Amex Gold benefits. Priority Check-in still exists for Silvers nowadays and most non-hub stations include Silvers in the SkyPriority check-in. At some stations, the dedicated Silver/ST Elite lane is often less crowded than the SkyPriority one (usually JFK T2 and T3, SLC). Another meaningful one is the ability to select exit row seats, that doesn't come with your Amex card. And I don't believe Amex Card Holders get the extra luggage on SkyTeam partners or DL International flights, that seems to be very meaningful. Also, the ability to call the Silver line and speak to a representative in less than 5 minutes (Although I don't recall waiting more than 1 or 2) doesn't come with the Amex Card. And of course, the most meaningful one is the ability to UPGRADE to First/Business Class, which in my case, has been >90% in 4 years, doesn't come with the Amex Card.

So, I guess Amex holders don't really enjoy the Meaningful benefits at all.