By "run a service" -- I mean, like the Ark or Arkade service, whatever the service that users have to hit in order to make a transaction. That's it. Obviously if a user is using Strike or Coinbase or PayPal, then that is the centralized "service" the user has to communicate with. I guess these L2s -- Spark, Ark, don't really "fix that issue either. They're not a privacy-preserving L2 like the Lightning Network. They can still aggregate your transaction data, IP address, user-agent, stuff like that, and then they have to turn it over, if, say, a certain government wanted to look at it. Maybe this is all expected, I'm still learning here.