Good question. I searched a while for info on this too. Not a whole lot of guys are using NG, but I did contact one member and he said even though the house NG is regulated, you still need one at the stand, to drop it into the range that works best for those burners. I also read a lot of places that you don't need one and they are a waste. That being said I got the one recommended
HERE and hooked it up to test (for $33). The point of it is so you can get a healthy (blue) flame even when those 10-tip burners are throttled down real low. I hooked it up and it did seem to allow me to get the blue flame at a lower flow rate when I throttled it down with the ball valve, but not a huge difference. On my setup it's not going to matter much though because I'm using a Honeywell 8200 valve for my direct fired MT burner, and that has a nice built-in regulator with precise control. My BK/HLT burner is going to run at full steam so I won't really need to regulate that. It cranks majorly when the ball valve is wide open. Tons of heat with solid blue flames. I've read these burners like to run at wide open. The venturi is setup to pull in air at a certain flow rate so when you drop below that you're dropping below it's intended use. You are to put the regulator before the ball valve, so you always have the pressure regulated, then you use the ball valve to throttle the flow to set the flame height. I'd say it's not a bad thing to try if you have problems getting a good flame at low throttle setting. Otherwise these burners run great off my house NG, nothing in line.