It is a custodial service yes.
Discussion
I guess we could add that a lot of services that are recently claiming to be "non-custodial" or "self-custodial" -- are basically full of shit, because if their service goes down, you're definitely not getting your sats. If you want to be fully self-custodial with a Lightning Address, you really need to run your own Lightning Node, and be sure your computer is online 24/7 .... If you can do that, then you should definitely do so... we actually encourage this and we have written extensive documentation how to do that -- you can start here: https://docs.megalithic.me/lightning-user-vs-lightning-runner/prerequisites