This guy is a world class RB which is a BIG fucking improvement considering we don't have a RB at all. I don't understand what some of you are bitching about?
All other options are far worse than him.
Fresneda is inexperienced and far from finished product. Even if we sign him he will probably go on loan.
Martinez is a defensive full back and we can't be sure if he is good enough. However, if we fail to sign Cancelo he would a logical second choice.
Foyth is way to expensive and far from a perfect RB solution for Barca. We should stay away from him.
With all that in mind, loaning Cancelo with an option to buy is by far the best solution right now. In addition to that we should be happy that we are FINALLY addressing our long term RB issue.