In order for HIVE to run on a Pi the specs on those would have to come up a bit more, mainly in RAM size.. Or the entire graphene engine beneath HIVE would need reworked in a way to allow it to run queries and replays concurrently on multiple threads of a CPU.. While possible in theory the cost in time and skill it would take to complete this is likely prohibitive sadly.
Interested to see how Eth 2.0 does honestly.. I for the record don't hate ETH but rather am dissapointed on how they destroyed what would otherwise be an amazing project by deciding to break the cardinal rule of allowing changes to a chain after blocks have gone past that height.
Will certainly have to look into these other projects. 0.3 second operation responses is fucking INSANE if it's actually able to confirm across the entire network that fast!
POW while cost prohibitive to attack almost all circumstances is an expensive way to secure a chain as far as energy consumption is concerned. Sure it's the original method and time tested but it's also archaic when you look at advances in other fields of IT work.
A truly "every mans" crypto that would favour proper decentralization and be resistant to stuff like mining farms or ASIC development that could be run by anyone ultimately would be the cure all for this.. Perhaps as global high speed internet becomes something accessible to everyone blockchain systems will piggyback on the infrastructure and ultimately become a widely used and accepted method of finance.