I spent 46 years in manufacturing, hands on, in machining, welding, heat treating, fabricating and fixture building. Probably made a couple hundred special tools for machine maintenance and personal hobby stuff. You definitely found a handy tool for spanner nuts, I’ve used a number of sizes just like the one you bought.
I made a tool for removing the carbon fiber tank valve off of an FX bottle gun. For whatever reason, the check valve in it dislodged and after filling (off of the gun) I unscrew the fiil adapter and all the air dumped. Had to find out why.
To get the valve off I just refused to use the common channel lock/ vise grip method. So I made a tool that slipped over the valve and had a hole drilled in it to go into the spanner holes in the tank valve. Clamp tool in bench vise, insert tank valve, align holes, insert shank of drill and tighten or loosen the valve. Worked perfect, and for the anally inclined, did not leave a mark on the valve.
If you have your own shop or work in one, it’s a piece of cake to make one.