Actually Ben did the add-on, but this one should be functionally the same, may be a little bit better.
But yeah, the idea is to have it integrated in the website itself and accessible from any browser instead of having people use a plugin.

Finally yes, I'd like to have it as an option, but this is just the first test-run iteration. It took quite a bit of cajoling it to make it do what I wanted it to do, so all those other things would be incremental improvements depending on the feedback we get and the availability of the devs.