the difference between zipties and velcro is that velcro is best for organizational binding... zipties are structural, and should be largely considered permanent. You shouldn't cut a ziptie holding a cable that would take down production any more than you should move a rack while production servers in it are still running. If it is the sort of thing you might want to move while the servers are running (like, say, ethernet, or a bundle of cables that goes to more than one server) like you said you should use velcro or something else temporary.
I don't want people trying to pop zip ties with knives near my cables carrying production traffic.