This is a great question. I think it could be interpreted either way but this is how we have interpreted it.
Our interpretation is no, as a SPO we are not providing a financial service any more than miners would be considered providing a financial service to the Bitcoin blockchain. We operate nodes that make blocks; our service is to the decentralized Cardano chain (technically you could say we are providing a service to anyone that sends a transaction that is included in one of our blocks, but there would be no way to know who that is). Delegators essentially "vote" on which stake pool they trust to make blocks. If they vote on a good pool, the Cardano protocol pays them rewards. They are not paid by the stake pool. The key difference here from a POW mining pool is the pool itself doesn't collect all the rewards first and then distribute them, i.e., we aren't accruing profits for delegators and distributing them. The Cardano network handles all of that.
I'd love to get anyone's thoughts on this. Thanks!