They didn't need to ban all other connectors..
So Apple could give people the ability to use their oh-so-superior Lightning cable while also being able to use USB-C for charging. If nothing else, it means that there are no longer any "does anyone have an iPhone charger" discussions at parties because people can just charge all their phones with USB-C.
That's a bit silly. There's only so much space in eg a phone.
(actually, which single-vendor connector are we mourning, here? I forget.)
So I'm not quite so sure why the EU needed to outlaw alternative chargers.
On the other hand: I used to work with a briefcase full of different phone cables, when the people that paid me had the swell idea to offer the service of transferring phone books between dumb phones and nobody agreed on how the connectors should be shaped. I think the number of them was >40. Some of them even looked identical in shape, but were not identical in function. Some were USB. Some were serial, with different voltages. Some used two data wires for serial comms, some used only one.
I was very pleased when we stopped doing that and I got to get rid of that stuff.
I'm also pleased that someone is making assurances that we won't go back to that way of doing things.
It's OK to have a common standard, and to stick with it. (It's also OK to draft a new standard when the old one turns old-and-busted somehow.)