ACME vs American/Stehl - turning explanations needed

I don't think a person has to be very smart to know that there for sure is more stress on the vehicles suspension, and also on the dolly's frame work, and that the tires are somewhat slipping on the pavement in the turns, but that don't mean it causes any serious problems,.....and apparently doesn't
This has all been hashed over many times, and they work ! And the price really should be a lot cheaper,....they are much cheaper to build w/o the steering built in.