Though the headset was fine yesterday, today I've found it quite painful to wear, so that strap looks like a good solution. It must be popular as it's out of stock!
Another solution is to buy a velcro bag strap cushion and put that on the headstrap.
I've been finding the headstrap isn't really grippy enough and it keeps sliding up. I've had to put the headset on tighter than I'd like to fix this, which makes it more uncomfortable, so I've temporarily put some bubblewrap around the bottom edge and this seems to make it more comfortable and stable, so some sort of velcro attached pad there might work.