Yup. Familiar with them.
"Proof of work" was a rationale idea back in the day, but then bitcoin mining started the energy current rounds of energy consumption for mostly useless compute, and it just got worse from there.
The main problem with micro payments is, you either need a trusted 3rd party aggregator, which gets you credit card payment processor style monopolies, or logging requirements for tracking transactions that cost more than the value they track.