Unfortunately, I lack the ability to properly communicate the experience of playing Magic as opposed to other games.

Given that we are at Lesswrong, the main point isn't about "communicating the experience". Even if you would succeed in communicating "the experience", that doesn't help anyone with doing an utility calculation with whether he ought to pick up Magic the Gathering.

Chess and Go have been Chess and Go for hundreds of years, and they've been studied to death. Relative to other classic games, Magic is a game that gives more rewards to experimentation and discovery.

I have Go experience but don't know much about Chess. I don't think the fact that Go is old stopped my at all from experimentation with various strategies.

Magic doesn't present players the task of dealing with ridiculous game trees but still manages to continuously present interesting decistions to make

Given that this is a forum for rationalists what's the issue with "ridiculous game trees"? If you already play an intellectual game, why not play one that provides a strong intellectual challenge?

5) It almost goes without saying, but playing Magic is fun and exciting.

I don't really but that magic is exiting and I have played it in the last. It doesn't compare in level of exicting to dance fast and intimate Salsa or Bachata with an attractive woman. The emotions that come up by playing a card game are comparably weak.

I don't want to say that it's not okay to do things for fun but, none of the things you listed say anything at all about providing benefits in other aspects of your life.

If you are a rationalist in search for a new hobby, pick one that's fun and that provides secondary benefits. To me it seems like you didn't seriously thought about the issue of whether playing magic is worthwhile. You just found yourself by accident playing MtG and it draw you in.

It interesting how hobbies draw people who are otherwise rational into them. If I would say on Lesswrong that you should seek a spiritual experience because it just provides an amazing experience that I can't even put into words, nobody would take me seriously. On the other hand one can say that one should play Magic the Gathering for those reasons because it's tribal behavior that's common under nerds.