Used to hate them, never used them, couldn't understand why 90% of the people that used them did so. Then when I started using a longer lens, sig150-600 C and then the DO, ans specifically started doing more birding, I got one for my 7DII. Holding the camera in portrait for long periods waiting for a bird to pose just right was straining my wrist.
Since I started using one, I now have one for my 5DIII as well for just general shooting, even though I shoot landscape most of the time and will just twist my wrist anyway to take a quick portrait shot or two. I just find it more comfortable and easier to manipulate the camera, even just changing lenses and such. I only take it off for hiking or when I specifically want to lighten it or make is smaller for packing.
It's just one of those things. No right or wrong, but I surprised myself, never thought I use one for general shooting.

