> you can't collect analytics on which IP address submitted a Bitcoin transaction

in many (most?) cases that’s obviously not true

>it’s not decentralized

yes, that’s the entire point. that’s how it’s able to offer better self custodial UX

> this will be a risk if a huge number of wallets use it as a back-end

I agree it’s a disaster if all mainstream wallets just use Spark on the backend. Or Arkade. We need a multitude of service providers and options.