What's "lesser" about the lesser ones and what are you going to do with the photos? You don't really need a 4000 euro digital back if you're only going to look at the photos on a phone screen, for instance. Do the "lesser" backs fail to meet your requirements?
I am not. I am asking genuine, neutral questions. I don't care one way or another what you spend money on. But, if you ask whether or not you should do something, I will question your motivation, since that is what will dictate whether or not you should do exactly that.
In other words, no one knows what you're using the camera for or what you're doing with the photos. There's no reason to eke any greater digital resolution out of the Hasselblad film plane than the maximum demanded for the best quality by your particular end use of the photos - just like the family snapshot album never really needed much better than what you could get from a 126 Instamatic.