It's just a bit of silliness for someone who wants to be flash.
I can't see that they are really practical.
I've seen a lovely Raven head top nock, again very decorative but not really practical as it was V bulky.
IMO form follows function, and it will look good if you stick to that mantra.
I had to replace the top nock on a bow made by one of the prolific Uk bow manufactures... it was stupidly long past the string but had very little horn below the string and predictably it split
Del
PS. I inlaid a gold arrow pass
it was for a bloke who had some gold rings that he wanted to melt down... I had some help from my mate Mick the blacksmith. It did the job and wouldn't adversely effect the performance.