The reason for proof of work is because true currencies are tied to labor, or more accurately, the potential amount of labor that can be converted from stored energy.
Now, a computer solving a math problem at a predetermined interval is not actual labor, but it does consume energy, and thus, currently the system is you have to spend real labor to purchase pretend labor, and you aren’t even getting the labor out of it, you are getting a token assuring you the labor actually happened.
Unless the computers are actually producing anything, I’m not sure how to get around this issue.