I'm not sure what's the point of selling L-BTC directly other than to mislead users into buying something they don't need. They could sell BTC and allow to "peg in" if someone wants to.
In a UX perspective, this is definitely the way to do it. Is it really hard to implement it in a way that the app would only convert the BTC to L-BTC, and just re-converts back to BTC once it arrives to the receiver? That way, in the user's perspective, it feels like he/she simply just transferred BTC. No need of selling a separate asset and all that jazz. Or am I missing something here in the technical side of things?