I have experienced 3 situations where I needed them (but I use them all the time anyway).
1. In Arizona it's mandated that you must keep the hose off the ground. I have read that some counties or cities also require it.
2. Had a strange situation where my site was level but the sewer hookup was behind me and uphill somewhat (but below the drain exit point of my 5er). In order for gravity to work, I needed hose supports otherwise the hose would have run uphill if it had to lay on the ground.
3. One time the dump connection was on an island next to me with a cement curb surrounding it. I needed the supports so that my hose didn't have to go up and over the curb.
I like and use the supports every time. Keeps the hose out of the mud, etc.
Tim