Is it evil to rent a sum of money?  In my opinion, absolutely!  Because interest to be paid on your loan, in simplistic terms, doesn't exist.  You must pay back the original principal + interest.  The interest portion doesn't exist and cannot be created out of thin air.

We, and the world, is in so much debt due to interest we can never pay back.  We should learn from history and not repeat the same mistakes.  Unfortunately, history always repeats itself and we'll also screw ourselves with bitcoins too.  Sigh.