I have a lot of windows with a lot of tabs open. I often will click on the nearest address bar to my mouse pointer and type just enough letters for it to say "Switch to Tab" and hit the existing instance of that commonly used page. The less than idea user experience for me is that the click potentially both switches the active window AND the open tab in that window regardless of what was running in it. For example, I often have a tab with video running in it in the corner of my screen and if the target window and tab happen to be shared, it'll switch away from what I was watching. I then have to stop what I was doing, reach over and drag the window to the Firefox window my attention was previously focused on, then go back to the second window to get my video tab back on top. It's enough mental context switching that I've found myself having to ask "wait, what was I doing again?" when done.
I propose that when a user types an address into the bar or select one from the associated pull-down, their intent is that whatever page they requested should appear in the tab they are currently looking at. The "Switch to Tab" functionality instead kicks them to the potentially distant screen location that happens to have what they wanted on it, forcing them to spend brain cycles moving it to where they wanted to work on it as well as undoing the effect of a tab switch in a window that may have been in use. An implementation that would be closer to the user intent could be a "Move tab here" button, which would replace the contents of the tab currently in focus with whatever tab "Switch to Tab" would have landed on. This leaves the other Windows undisturbed (with the exception of a tab being removed) and moves the information to where the user would have been working with it had they not pulled a second copy of a web resource rather than using switch to tab.