Yeah, I don't think those are really HSMs. Just a very secure USB stick. The whole idea behind an actual HSM is that you never trust any computer it is plugged

Yeah, I don't think those are really HSMs. Just a very secure USB stick. The whole idea behind an actual HSM is that you never trust any computer it is plugged into, it is designed to be impossible to retrieve the key stored in the device via any means. All signing operations are done internally in the device itself - you simply can't mess up and accidentally leak key information.