So I wanted to make the hotkey something super easy, to configure the inserters, so I tried alt+leftclick. This seems great at first, but the issue is that when you configure an inserter, the first click is fine (enter configuration mode), the next clicks are fine (changing base-direction, or configuring pickup spot), but then when you do the final click, to set the dropoff spot, it ALSO builds an inserter right there, as if you regular-left clicked. So it's not "stealing" the left click like you'd want it to.
However, alt-click doesn't steal left click in the first place, as, for example, if I hold a stone furnace, and alt+left click, it does just build the furnace normally.
I realize this might be something that is impossible to fix, due to what you may or may not be able to do regarding left click, but I figured I'd report it at least!