Well, I'd suggest that the fact that they were financially able to carry out this operation suggests that they provide enough value to others for it to be a net gain. Money doesn't necessarily indicate value, of course, but it's a decent first approximation, especially for a business like theirs.
with that essential caveat, this is a very good point. My backup drive died in the midst of this crisis, and I specifically chose to use backblaze instead of buying a new drive. Obviously, it's not a 1-to-1 tradeoff in terms of functionality, but it was close enough for this data that I felt like I was better off paying them monthly than paying an inflated drive price upfront; they were drive farming for me by proxy.