Old Colt Cone-Front Recoil Plugs?

I've seen these on older Gold Cups but don't think they are used on the current NON-DCM compliant ones.

How much did that help accuracy?

Is it a good way to use spring pre-loading to keep the barrel and bushing pressed up into the slide the same way every time? Or is that even a factor when the bushing is an interference fit in the slide, fitted per NM modifications? But what about keeping consistent lock-up as parts wear?

Also wondering why it didn't catch on with other makers, and whether cost of production alone was why Cold doesn't do that any more.