The button is bloat. It bloats the UI by default. It bloats the overall package.
The code to insert the button into the UI by default is bloat.
The code to pop up a message telling people how great it is is bloat.
The code to support the standard is bloat.
The "standard" itself is bloat.
I want a build of Firefox without this shit or any of the shitty recent additions like it. Disabling it (or however much of it you can) isn't a fix because it's still resident, still takes up storage space, still needs to be updated when there are security issues, still wastes time and money in development, etc.
They don't fucking understand what people liked about Firefox.
Hint: Fast, flexible, extensible, lean, secure, reliable.
Over the past few years it's gotten relatively slower, less flexible, fatter, less secure (largely as a result of all the new insecure bloaty shit they add in), and less reliable.
Hell, just last month I had to do a complete wipe of Firefox because the fucking internal database was broken as shit after some update and the "Awesome Bar" wasn't pulling from any history past the date it broke (even though all the subsequent history entries were present). I can no longer tell Firefox to remember my browsing history but not to remember the download history. I can't tell Firefox to tie into the standard cert store on any OS, making site-wide management a pain in the ass (you have to use their own half-working, half-documented command line tool and maintain a separate copy of all certs) and making trust pinning nearly impossible. I can't do half the shit I used to be able to do with Firefox because some fucking asshat at Mozilla decided that I didn't need to.