Massive premine on Chia, didn’t know that. I have a hard time believing that many nodes are reachable, there are probably about that many users in general, if that. Looking at the latest dozen blocks right now, they’re completely empty.
Their software runs a full node and a wallet, so most users are a node by default (if I’m not mistaken) and rewards are double for the first couple years. You can run their software and just about anything, low powered CPU’s, pi’s, NAS, etc. So I don’t doubt their numbers are too far from the truth, esp considering how much China supports them. Nodes have been slowly dropping over time as the crypto boom cycle has died down.
As far as real transactions, they’ve got a way to go. Just releasing NFT support a few months ago.
In the beginning everyone had to run a full node even if they weren’t farming (in Chia instead of mining it’s 2 stages, first plotting and then farming) but earlier this year Chia released a new light wallet which doesn’t run a full node. Now it should be mostly actual farmers that run full nodes. Chia currently has 22 EiB of netspace which would be more than 1.5 million of 14 TB hard drives.