In terms of function, there is a case to be made for nickel on at least a couple of points. Where the argument breaks down is when it drifts into aesthetics-highly subjective and predicated on personal tastes.
From a functional standpoint I favor the processes which utilize an electrochemical bond with the base material over those where it's essentially mechanical, as it is in 'traditional' electroplating.
Even where no substrate material such as copper is used, the adhesion of the traditional electroplated finishes is relatively tenuous and peeling/flaking can result from nearly microscopic defects in the surface finish due to the infiltration of moisture, solvents or oils. Their practicality as an aftermarket option on machinery with typically close and critical tolerances, such as firearms, is limited to a great extent by the comparatively large dimensional changes inherent in the process and the difficulty in obtaining uniform application to all surfaces, IMO.
The 'electroless' processes offer vastly improved adhesion, more easily controlled uniformity of application, and better longterm resistance to both corrosion and wear. However, it is almost impossible to get the true 'mirror' finish found on articles using the older processes. It can come close when applied over a first-rate polishing job, but any surface imperfections will be easily seen as the contrast will be emphasized rather than hidden. IMO, that's a primary reason why most factory and aftermarket electroless finishes are generally applied over a 'brushed' or 'bead blasted' surface.
I have a couple of handguns with some form of proprietary electroless finish on them. While I don't know the exact compositions, there seems to be little difference in how well they've held up under use so far as there's been virtually no deterioration from either corrosion or wear under extended firing and carry. My Star M-43 has their "Starvel", my full-sized EAA Witness their "Wonderfinish", and an older Colt "Combat Commander" has straight electroless nickel. I also have an old customized S&W 1917 with Armolloy and a Keltec P-11 with the 'hard chrome' slide. All of them are holding up just dandy. The only thing I have with the 'traditional' mirror finish is a replica 1858 Remington .44. It's holding up well so far with limited use, too. The main reason that I use my blued replicas more often is that the way light reflects off of the nickeled one makes it tougher to shoot well as the 'sights' virtually disappear even in relatively overcast conditions.
Won't offer an opinion as far as 'decorative' value goes. All I can say is that those who like the flashy mirror finish find it to be the sort of thing they like, and if that's the way they roll - Roll On!