To realize this concept there can be internal exchange on back end server with enough reserve of both currencies auto-converting instantly in both sides at average market rates. It can be also done in cooperation with a real external exchange. But probably internal or even decentralized system can have much more benefits.
If all of this can operate seamless for end users with light weight client wallets - a lot of people will prefer to store their money in private Monero while keeping an ability to use all the exploding Bitcoin infrastructure.
this was suggested before, seamless xmr/btc conversion sounds really awesome
Wow, this would be such a great feature