I'm not sure it's sensible to think about one kind of transport in isolation. First, a lot of users of e-scooters will have driving licences (and therefore training), and some will have done cycle training. Second, it would be hard to make a case for compulsory training, licences or whatever for e-scooters and not for e-bikes. Legally (in the UK), those latter are just bikes, so therefore also for bikes.
I assume that one aim of the trials is to see how many problems e-scooters really cause, as opposed to doing everything according to prejudice and perception. Since ordinary bikes are assumed by many to be far more dangerous than they are, I wouldn't want other modes handled by perception either. As things stand, licensing, insurance and the rest are applied to our motor vehicles because of the proven, substantial level of extra danger that those bring. Let's make sure that we don't muddy the waters.
I've never ridden either an e-bike or an e-scooter, by the way.