You certainly would minimize your brake pad wear with any EV, especially with the i3 if driven properly. Plugging in is not a big deal, but maybe bigger in the UK where you'd have to coil and uncoil the cord each time. The EVSE's in the USA have a cable tethered to the EVSE, but that is not the case in Europe. Still, it should not take much more than a minute. Not knowing the total distance of your typical trip, you might find that the BEV would work for you as well. The car does not use much power when it is not moving, and the REx is less efficient, especially at heating than the BEV (the BEV has a heat pump (standard in the USA, not sure about Europe) while the REx must rely on electrical resistance heating, which is much less efficient). Plus, the REx, being heavier, creates a hit on efficiency. Now, having the REx may mean you might get by with it as your only vehicle, and you have to consider that as well. It wouldn't suffice for my driving needs, but might for yours, which is why I bought the BEV verses the REx...we have few CCS charging units where I live, and my typical trip would be an annoyance trying to use the REx on petrol most of the way.
2011 535i x-drive GT, 2014 i3 BEV