In most web browsers, middle click closes tabs, opens links in new tabs, and on Windows, starts an automatic "scroll follows mouse" mode. I seem to remember that at one point, Chromium on Linux would interpret middle clicking on an unclickable part of the page to mean "interpret the text stored in the clipboard as a URL or search term, and go to it." Imagine the fun I had with the occasional misclick of a link before I found an extension that implements Windows-like middle click scroll.
The only time I ever intentionally use middle click paste is when using the terminal where, you know, Ctrl-C and Ctrl-V are already taken. An option to disable middle click paste for everything but terminal emulators could only be a benefit, removing a rare but ever present source of confusion and mistakes.
> Chromium on Linux would interpret middle clicking on an unclickable part of the page to mean "interpret the text stored in the clipboard as a URL or search term, and go to it." Imagine the fun I had with the occasional misclick of a link before I found an extension that implements Windows-like middle click scroll
Opera does that, too, and I love it. No need to focus the address bar after selecting text, just click and go :)
The only time I ever intentionally use middle click paste is when using the terminal where, you know, Ctrl-C and Ctrl-V are already taken. An option to disable middle click paste for everything but terminal emulators could only be a benefit, removing a rare but ever present source of confusion and mistakes.