Correct! The main benefit is that you can create a web/mobile application which makes use of Lightning invoices but delegate the tx infrastructure (signing, route finding etc) off to a service provider (e.g Bluewallet).

If you're looking to push further into the mobile world, but would like full node capabilities, BDK and LDK both support Compact Filters (https://docs.rs/bdk/latest/bdk/blockchain/compact_filters/index.html) to implement BIP157. That means you don't need to download the full chain but also don't have to compromise on validity.

Thanks for sharing, especially the WebLN resource! Can this open up mobile apps such as BlueWallet (supports WebLN) for payment completion? If I can avoid needing to sync/run a full node while getting started that would be ideal haha.