Honestly?...Nothing really. He's just getting a young dog some time in. You gotta give the dogs time and coyotes to learn their trade.
If the sole purpose was killing that coyote, he could have done so at any time.
But,...here's the REAL purpose behind a stand like that,...multiple coyotes.
And THAT is where having dogs like those really make a huge difference. If there had been more than one coyote show up on that stand, he could have shot that one, and then the dogs would have brought the other one back in too.
If you were just sitting out there calling without a dog, and you shot one but couldn't get on the other before it bugged out,...It's gone and chances are it's not coming back.
Having dogs out there, with the right sounds playing changes the game with multiple coyotes.
"Style" plays into it quite a bit too. Different guys expect different stuff out of their dogs. A lot of these guys will let their dogs "work" the coyotes for quite some time just to let the stand play out, or sometimes just to get good video footage. And, sometimes it's because it's what they enjoy.
Some guys don't want their dog more than 20 yards from them. Basically acting as a "stationary" decoy.
Some guys, like their dogs sitting next to them while their calling acting as "radar" with their eyes and nose, and then engaging the coyote with the grab ass and cat and mouse game, all the while hoping it'll draw other coyotes out of the brush. (I prefer this method because you get to witness the action, and I'm not totally secure with the idea of my dog being out there for extended periods of time)
And, some guys want their dogs out there hunting for coyotes the whole time. Sometimes a long long way out there.
I've been able to hunt with a dog like this, and it's amazing to watch!
My buddy had this young Catahoula male that ranged way out there. We'd set up in this corner, and off goes Mac! I could see him out there at the mile fence line when I heard coyotes bark howling in the draw on the next property. Mac looks that direction and off he goes!
About 20 minutes later he comes back into view with 3 coyotes in tow at a trot. They made it to the 1/2 mile mark, but turned around and headed back. In their mind, they'd ran him off and I think it was also a territorial boundary line.
So, he turns around and heads back to them!
This went on and on, but the closest they'd come was about 350 yards, and I whiffed the shot!
It was way cool to watch him do his thing though!
Later that day, a guy drove up from Oklahoma and my buddy sold him! Not his style, but a style some guys would die for.