Only drawback appears to be size and time spent maintaining it.
That's right. You have to have the time you need for trial and error. People of the past did all these different procedures, and today's technology is the result. Of course, it's fun to do an experiment when you don't have a day job to earn your bread (including the typical other chores).
So while there is a lot of hype about "sustainability" and the like, individuals are using the existing grid and technology - high amounts of provisioned energy in the form of running servers, for example - to promote a "better world". There is nothing particularly sustainable about using cryptocurrencies to make money in order to have free space for research. It's the way it's always been: there are people from whom everyone profits indirectly. People who don't have a day job as employees profit from those who do. The question of whether the profit also comes back to them is always open. In order to have a return, an application must be sold and advertised en masse. Otherwise, it remains a niche and is run by a small number of people. There is nothing wrong with that either. The only flaw I see is that it is advertised as making the world a better place out of conviction.
I see it more as a hobby. Something to keep the mind occupied and to experience oneself as meaningful. Nothing wrong with that, but it doesn't make the world a better place (whatever that means). Though it makes my life better or more exciting and meaningful, if I have the luxury to get past the treadmill.