No, no spacers. I did have to remove that 12-speed cassette hub and attach the traditional cassette hub to accept the 8-11 cassette design that most of us are familiar with...super easy to do. People who want to run the 50+ cassette cog setups are obviously free to do so, but I don't think it's necessary on most of these emtb's with stronger motors like the Bosch-4 and others.
With my 11-36 9-speed gearing, for fun I've shifted down to the 36T cog, and the bike is practically unrideable. It pretty much just wants to launch or wheelie...LOL! Now, I am riding in Turbo, and I'm sure it would be different in those lower power selections, but I just don't ride there. Understand that I'm not trying to preach or rail against the 50+ tooth cassettes or riding in lower power ranges, but if you're a Turbo choice rider then maybe there's no need for 12 cogs and super low gearing.
Again, I'm a dirt motorcycle guy so my approach to riding may be different than others. Also, if you're riding in locations where extreme battery conservation is necessary, then lower power and higher gearing is more understandable. It's all about choices and applications.