Main thing about a ring is it gives you the opportunity to clip a second tie-in to the same ring but still have the same balance point on the bridge. Of course rings are the entry drug to bridge swivels, and oh don't forget double bridges ;-) My current setup is a swivel on one bridge and a ring on the other, you can have it both ways.
But... yes a nice DMM swivel for example is expensive, and the bridge will eventually wear a groove in it, even you flip it regularly upside down like a chain saw bar. It's all about what you find works best for your evolving climbing style, gear wear (as Evo mentioned) is the lesser issue, gear wears and you just want to inspect regularly to stay on top of it.
You can spike your bridge with a carabiner (biner through a slip knot) on the stitched end side of your bridge to find a bridge length that works better for you with your current long bridge. That will help you decide what "permanent" length to go with. In regard to Jonny's comment "think a double over hand stopper knot will work on that Petzl bridge D?". It's worked great on all the other rope bridge harnesses for years, no reason why not. Just set it well and after one work session you won't be able to untie it anyway ;-) Keep the sewn stopper already on the bridge cord and you have a guarantee to never slip core or cover through the double overhand.
-AJ