This revelation alone makes the time spent submitting the PR worth it to me.  Of the $6450 I put into my HSA, I keep $2000 in cash and the rest as Vanguard 500 Index Fund. I'll do everything I can to keep from tapping it since I believe this investment to be the best deal around. 

There is no other investment that is both tax-free on the way in, and tax-free on the way out, including gains. So long as you use it on health related expenses, which you will always have.