I agree with riding as many as you can swing a leg over. But like any big purchase, you'll probably second-guess whatever you choose.
When I was at Davis over the weekend, one of my friends joked, "when you buy an e-bike, plan on buying two... since one of them will probably be in the shop..." IIRC, he has a Canyon and the local shop is waiting on parts from Shimano to repair it. That said, he has a history of breaking almost every bike he's owned and currently has back-ups for just all of his trail and enduro bikes. He lives near Davis and rides rocky tech trails almost exclusively now and between that and his "bull in a china shop" riding style means he breaks bikes.
I'll admit I've become familiar enough with the Moterra SL that I may very well buy one to have as a back-up. Or the demo if/when it becomes available. Although, to be honest - my issue is space and I don't really have room for the bike I have on order - which will be bike #7 - much less a #8.
It was interesting how in that video they really don't consider the motor system to be a deciding factor when choosing a bike. The differences are somewhat subtle and not difficult to get used to.