Fire Emblem maps are VERY smalls, and are made more like puzzles than real strategic battles. They are fun, but On the Switch, they would feel too light. On mobile, they are perfect to play while waiting for the bus or subway.
Mario is very close to 2D Mario, but the always running gameplay make it more like a "parcours" game, and memorizing the different platforms pattern is key. The innovation here is the fact it's a very action gameplay, and that it works on mobile, something very hard to do. But if it was on Switch, it would be fun for maybe a day or two, then after you would wonder why you bought that instead of NSMBU or Odyssey.
Didn't really play Animal Crossing, but again, it's very barebone compared to the original game. It's a very small sandbox, and the options are very limited.
So yeah, they are worth playing, but they are designed with mobile in mind, they are not "the next big game in the series", they are alternatives for people that don't have access to a Switch or 3DS (be it because they don't have one, or they don't have it with them).
I like the little sausages on a toothpicks there is sometimes in banquets, but I don't miss them when they don't have them, as long as the banquet is there. It's very similar, IMHO.