Because I like to be in a routine. I don't want a beer club that sends me that many beers. I wouldn't mind a 6 pack sampler every month. I haven't searched that hard, but maybe there are some good ones out there that will send a 6 pack sampler.
There are those that will send you a 12 pack every 4 months. That might work for you.
I have received the beer of the month as a gift in the past. Mostly good, although I could have done without some of what I received. However, I had it at a time when my local liquor store didn't have a 100 foot wall of microbrews, 1/4 of which are rotating. The club is still a good way to get a wide sampling of styles. It's a very good introductory course into beer.