Perhaps sometime in the future the eXch team will rework the anatomy of the drop-down list so that the "Exchange rate not found for BTC/BTC" notification is instantly displayed when you select "BTC/BTC".
I
think this will require javascript, and as far as I can see, eXch does not have anything other than html and a bootstrap css script in their main page. It's good that they have taken care of not including bloatware in the front-end; most of the operations happen on the back-end, as should.
They have not stated eXch is non-javascript AFAIK, so they might introduce it at some point, even though I don't see a reason. Being told that BTC/BTC is not available, might be discomforting (for those who want to mix?), but it's harmless.
Question: I see that
affiliation program is available. If so, since eXch is non-KYC, what prevents someone from using their own affiliation link when exchanging to, essentially, reduce the fee?