Nailed it!

Zeus started out as just a way to have a mobile wallet that was connected to a node you were running elsewhere, like on an Umbrel or Start9. They were THE go-to for this, with the possible exception of BlueWallet, but I don't think BlueWallet has as many options for how to connect to your node.

It's only comparatively recently that Zeus added the node-in-the phone "Embedded LND" option.