I don't know that it is controversial as much as over-used, or perhaps more correctly, unnecessarily used in most of the cases where it is.
There's a thread for folks to post their
Selective Color Images here, and there are obviously fans of the genre. I've used it on several occasions, usually to either highlight a subject, subtract from background noise, or a little of each...
With the first, I wanted to accentuate the color of the fire without oversaturating, so I selectively desaturated everything beyond a point. With the second, I really liked the capture of the ribbon, but it didn't stand out the way I wanted it to in a full color or B&W image...
The main thing is, as with any technique, to use it where
you feel it's appropriate and don't just use it simply because you can. When you use something just because it's in your toolbox you wind up building something with just a hammer, and while it's a sense of accomplishment and fully functional, others often don't appreciate it as much as the person who did it.
And please, don't take my words to be discouraging. If you like the technique then practice with it, and look for feedback, because this is one of those techniques where collecting criticism is almost more important than listening to advice as it will help you focus on how and where to use it.