Hello Bugsy,
I see it as simply marketing, companies trying to get you to buy new lines. Maybe they are just creating or catering to the newest fad or trend... I dunno
I have watched 2 nearly equally skilled,
excellent fishermen work a river side by side and they both had about the same number of takes. One had fluro orange the other dark olive, they even laughed about the colour controversy when I asked them.

The
best of the two even brags about owning a cheap rod & reel.

That said I think a dull line may help when fishing over spooky high pressured fish... that and I don't like loud fluorescent lines.