That's my assumption as well. Probably can sell the points and pay for the S. Regis and still have change.
Yup. SPG50, SPG355N and similar often give good deals.
On the other hand, some people don't sell their points so if you have enough of them, why not.
And while youre going to BOB, it may be well worth looking at other hotels besides the chains.
Though many have a hard time wrapping their head around spending $800-$1000+/night.