I do absolutely think integrating into the deeper features and functionality of fonts and opentype is what will make it work! Making it work well with existing font design software is also super important for typedesigners.
They've probably built something no one wanted and their launch success makes it hard to see between the lines. This is always been a problem with tech giants coming out with new products.
I sometimes even wonder if it's better to launch products like these under a different name/umbrella so that they can get some real users.
I think I am convinced, my wording here definitely does not help ('good' -> 'possible'). For sure a new feature does not warranty intrusive browser behaviour. Will make some edits.
I am (at some point)! I actually built this as a somewhat hack to get users whom I can interview. There were 2 existing extensions that had similar features and I built this to replace them.