All the other buttons on that selector have well-defined uses, but I have not yet found a situation where I have wanted to use HOV. It makes a good demonstration on conversion to type, to show a hands-off hover and even smack the cyclic to show how it restores itself, but unless you have a big airfield to drift over, it is not particularly accurate.
Too much residual drift requiring constant trim inputs for any useful hovering. Do it manually.
SAR birds have more swept-up inputs which may include doppler positioning to hold a spot over the ground. Adds a lot to the cost.