My vote goes for rogue watchmakers with customers wanting a cool orange hand as replacement. I have seen this on many dress seamasters as well.
This is of course speculation, but I doubt that Omega would use the orange seconds hand as a replacement. (I think I have also only seen this orange version used as a sweeping seconds on watches with chrono functionality).
With that said the original seconds hands don't extend (much?) further than the orange one.
Here's a good reference watch:
https://omegaforums.net/threads/near-perfect-mint-omega-seamaster-120-diver-136-027-w-papers.78137/Click to expand...