I don't need to run it on more than one computer at a time, but given the churn that occurs, upgrading/swapping computer hardware in the course of experimenting I don't want to get locked to one PC and then have that croak on me. I've been burned by copy protection in the past and it always leaves a bad taste in my mouth. In some cases the protection was such a hassle that as a legitimate paid user I still had to go download a crack to bypass it. The fact that you're willing to work with a user to get it transferred to a new machine is nice, although I'm still a little paranoid about losing support a few years down the road when hardware fails and I have many hours invested in content.
It may be different with a niche product like this, but the usual observation is that a software product gets cracked within a very short time of being on the market, at which point the protection is a hassle for legitimate users and the pirated version is more convenient. I'm an honest user, I pay for my software (and music) but I'm bothered in principal by DRM and protection schemes and avoid them when possible.