I still use that button but only to easily find the RSS link because it can be hidden sometimes (I then load it up in another RSS reader).
Now they're getting rid of it, i.e. you can't simply add it to the button back in. But of course, there will probably be an extension that does that.
And then another draconian compatibility-breaking change to the extensions APIs will permanently disable said extension a year later...
But I guess you're probably sour from WebExtensions being introduced in the first place. Which I can understand, because it did lead to many extensions no longer working. Still, it should lead to that problem being one of the past.