I do purchase my AS lounge membership each year because for me it works. I like the idea that during busy times the crowds are for the most part actual board members. What I really miss is something available at MSP (but so far I am really preferring the Escape lounge over the DL Sky club that I used to use often)
For me, as a solo traveler, I just need a seat with power, sometimes a place to work with power. Sometimes I would like a glass of wine, and maybe a salad or/or soup while I work. I also really appreciate the ability to use the Admirals club and United lounges when at other airports. Sitting at an airport restaurant, or at the gate area just is not as conducive to working for me.
So, all in all, I am in favor of reserving spaces in the AS lounges for AS Lounge members