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.
One reason to buy L-BTC instead: You can transfer it faster and more cheaply, assuming you're sending to compatible services. If someone is just buying coins to send to an exchange, then BTC might be slow and costly by comparison.
Considering that compatible services are nearly non-existent it looks like a trap. Perhaps if it was easily convertible both ways inside the app itself it would be ok I guess. Is it?
IIRC peg-out was possible only via exchanges, mostly centralized/KYC ones. If the app helps to overcome this - great, but I kinda doubt it.