That would be interesting. Not the Trojan horse you’re thinking of... but using it instead for good. One of the downsides to f@h is you aren’t compensated at all for your contributions. Now obviously that’s not such a big deal, since you’re ostensibly doing something altruistic for society and your fellow man/woman.
However... if you put a real cryptocurrency behind it and coupled proof of work to solving real scientific issues... that could bring a lot more compute into the cluster.
This concept is called "proof of useful work" and we haven't really found practical examples of it yet.
(There are also systems that pay people with cryptocurrencies for contributing computational resources, but the cloud computing markets are probably efficient enough that you could get cheaper computation overall by paying cloud providers regular money to rent computers from them.)
Proof of useful work, in which the cryptocurrency itself is verified by people who are also doing inherently useful computation, has a big challenge because the properties of the problems that are used in cryptocurrency PoW are so specific. Partial hash collisions, the typical example, have properties like
* it's trivial to generate a practically unlimited number of new instances
* new instances can be created in an objective way with no ongoing involvement by a central authority
* the instances can be parameterized by an arbitrary seed value (representing the identity of a block)
* the instances can easily be scaled by an adjustable difficulty
* a purported solution can be verified extremely cheaply
I don't believe we've found any broadly useful computation problems that have all of these properties.