You may want to read the rules. There are sanctioned ama fields and what are called park flyers. Their rules are actually very similar to the faa when it comes to where you can fly and are covered. Ama has been around for decades and prior to the last few recent years were focused on ama sanctioned fields. There would be times where ama insurance can help you but in a lot of cases you see online they would not.
It is important to note that they are and have been fighting for the rights of radio controlled aircraft and pilots for decades and they really seem to be the only ones who have made any progress, which is a good thing.
It is two different worlds out there. Unless you are drone racing or flying in a pattern most ama fields would not interest drone flyers as they are out for video content, and flying over the same field over and over can get boring. Most people on here want to fly all over which in a lot of cases the ama rules are not geared towards. It is going to take time to see where the dust settles
I did quickly look over the rules, like you stated, they are reminiscent of FAA reg's. and common sense. I wasn't going to be bothered with them since I was going the 107 RPIC route, but none the less, its a good organization, good cause, and likeness if this does evolve, I already, now have my membership in hand, since they are doing things to fight for the RC community. Just as well I keep my AOPA membership valid, for same reason, as they are also both overlapping with drones.
What struck me, and brought all this on, is that I am under the 5 mile vail of Class C airport ( 3 miles, actual) I called up spent time trying to get the right ppl and finally got the tower, and the guy who did know what was going on, asked if I was going to operate under 101 or 107. I declined my flight and information provided to ATC, until I knew more of 101. Which I found out it was a regulation almost made for the AMA. ( all this just to fly 200 ft above my home. lol ) So I joined the AMA and will be getting my RPIC added too my pilot ticket, just so I am operating under FAA regs no matter which way I decide to fly.
I do have a state park that allows pilots of the AMA to fly (field 9) however, I have to also invest in a permit for that park and as well a club that will be associated too it, like you said, we are also doing this for other types of flying (photo/video) than FPV, so that can get boring. Plus its a heavy investment, of AMA + Club + Permit to do every year.