Centerpin fishing reels have a long history in England. Here is an excellent reference article:
Simply put, a center pin reel is a large fly reel that rides on bearing with no mechanical drag. The drag is applied with the palm of your hand!
In the Pacific Northwest they are used when float fishing for Steelhead in rivers. The advantage of free spooling as the float is drifting down stream is nice. Before I decided to shorten my 13′ rod with the car door I enjoyed using them for summer runs on the local rivers and streams. I was able to hook and land one summer run after several trips. Fighting these fish with no drag, light line leader and 10lb mono main and long rods is fun and challenging.
Casting the the setup is a true art form that I have not fully mastered. Some cast off the side of the reel. Others start the spool spinning before the forward movement of the cast. I can say from experience that I was able to create the finest rat nest ever made with this reel with little to no effort. These reels require your constant attention. I suppose you get used to having your pinky finger constantly riding on the lip of the reel, but it sure takes practice.
As far as maintenance, one single bearing! Keep her clean and fast and that is all you need. Since these are used predominately in fresh water, corrosion protection is not really a concern.