[innocenat]

If it's only for open in new tab, then Ctrl+Left Click work as well when using trackpad.

[fendy3002]

Middle click is very useful to close tab, which the alternative is to move cursor to a much smaller close button.

Especially on some apps (iirc pgadmin) where the tabs has no close button, that we need to right click and choose a menu to close a tab.

[hgomersall]

Pasting from the primary buffer is surely the main use case for middle click?