Folding at home can track user contributions and issue micro/payments as they see fit. Crucially, this does not need an immutable chain of truth to do.
Instead, if we added a blockchain, then we would require 2 sets of participants - those who run the useful simulations for science, and those who run the useless calculations for the blockchain. A complete waste of resources.
Maybe you run a private platform too like git/GitHub if there are real world payments and user accounts, but I wonder why couldn't that technology be used? Does "blockchain" just have an irreparably bad name at this point?