1. Moving around made building a career an impossibility for my brilliant wife, because military bases are typically situated a ways away from major economic zones.
2. This will improve retention because there is a lot of pressure on the (relatively underpaid) service member to make ends meet, especially when the best your spouse can do is like, become a realtor.
3. Great for employers. IMO (and you can fight me on this one) military families embrace duty, leadership, and hard work. If you can hire a vet or their spouse, you're going to get more out of them.
4. Great for military bases/areas which are typically economically depressed.
5. Great for family life. When I was in I was deployed for almost half of our marriage. That was really tough on my wife with nothing to do. A lot of spouses can't handle that, get into trouble, put undue pressure on the marriage, etc. For those of you who've ever been in an FRG you know what I'm talking about ;)