I thought it was a good idea and liked using it. I do not see how the old "global" h1, h2, h3... system we still have to use is any better.
I wish there was a neutral <h> element that could then be specified at an arbitrary <h~n~> sometimes I have documents that have headings 8 levels deep.
It's like if you removed relative paths and working directories from all OSes. A lot of things become really annoying to do.