The only issue here is growth in Blockchain. I'm not download 50GB of crypto trash to mine virtual coins and i don't trust web wallets. The more popular the cryptocurrency is, the faster its blockchain grows and the more electricity it consumes to read/computer/transfer all that data, regardless of algorithm(i.e. even its speicifically low-energy, it still have to use more resources as size of blockchain grows). And no, "pruning" and compressing the blockchain only delays the inevitable.