Beware.
By converting immediately to AA miles, you lose one thing: if you convert 20K star points to AA miles, you get 25K miles. Thus, it's 1.25 : 1. By converting immediately, you don't get this.
My comments about star points (I have a starwood Amex, and I actually keep them as star points, without converting): I was able to stay recently in the Westin in Rome in a ~$500/night room (got upgraded to one half of the presidential suite) for free using Star points. For European travel, one can do very well with star points.
Finally, to me the main advantage of starwood gold is the ability to get a late checkout (4 pm) just by requesting.
p.s. The St. Regis is on Central Park South (north of 57th) between 6th and 7th.
Cheers.
Cheers.