Again, it will depend on your location. There are a few boats in our marina that have "permanent" dock lines attached to the bull rails, or cleats if their dock has them. But I would say 90 percent or more of the boats in this area take their mooring lines with them. Nowhere we go has mooring lines ready to use--- you have to bring your own, so you might as well bring along the set you use in your own slip. That way they're already made up and attached to the boat so they're basically ready to use when you need them.
Like many people, we do have a permanent spring line attached to the outside end of our dock with the loop hung on a PVC pipe a little higher then the railing on the GB. We use it when we come in because the wind is almost always blowing us hard off our dock into our slipmate, so my wife takes the line off the PVC hook and puts it around the center cleat. I come forward against the line and then with one engine in fwd and rudders hard over I can bring the boat back against the wind to the dock and pin it there while we get the other lines to the dock.
Taking your mooring lines with you is not technically wrong. Anything that works in a particular situation is technically correct
What works on the east coast may won't work in the PNW and what works on a river may not work on a lake, and so on. This business about "you have to do it this exact way or it's wrong" is crap. Even the US Navy, who everyone seems to accept as an authority on boating, says in the edition of the Bluejacket's Manual I have that (I'm paraphrasing) "Here's the best way to do it but if circumstances dictate a different way, then do it that way."