Interested to hear your own stories.
This feature is really only useful if you need a specific amount of coins in the first place.
For example, if you have to pay an invoice in BTC and all you've got on you is LTC which you want to exchange, and you don't want the exchange rate to be floating because you may overpay/underpay as a result.
Essentially, it's a temporary hedged position. That's all that it is.
For those who are saying that it's only useful for large transactions, I'd beg to differ. a) large traders wouldn't use Changelly or any other instant exchangers anyhow and b) this fixed rate system benefits small scale users the same way.
Could you please explain why instant exchanges won't fit?
Other points - I see, ok.