with the direct upgrade and needed visual indication, you might as well give the player the option to directly build the 'electrified belt', if i may call it that way.
One should definetly be able to directly upgrade the belt if possible, though you'd have to do 2 actions to create an electrified conveyor line, while you could just instantly
build it from the menu. Both ways would be useful, i guess.
Item elevators, splitters and mergers would also be necessary, sure, but that would just be the way it goes with such a feature.
I think even though it might seem a bit much at first, players would get used to it relatively quickly.