The incentives are

- you get to use your hard-earned 100k status
- you continue to earn towards MM status
- you earn a lot of redeemable miles
- you don’t have to sweat it when partner EQMs don’t post in a timely fashion (or at all)

Obviously, if you don’t have to fly at all, you might be able to find something better to do with your time and money. But the alternative, shifting business to another airline after you reach 100k and start from scratch or fly with lower status because the additional EQM on AS aren’t valued might make little sense unless you will continuously maintain status in two programs (and probably only if in different alliances).