Sometimes for some. No cartridge will kill anything any faster than another cartridge. What kills is the shooter's ability to place the bullet he's using in the right spot! But what the bullet does do is destroy thing's! Bullet coming apart destroys pelts. Think about the bullet your using and where to place it. If I were hunting coyotes a lot, I don't, I'd give a lot of thought to going with a heavier bullet but using quite a bit lower velocity. Slower tuffer bullet won't come apart as bad especially when used at lower velocity. And the slower tuffer bullet will kill just a quick if properly placed. I think if I was a serious coyote hunter and selling pelts I'd go with hard cast bullets at lower velocity. Probably means you'd have to plan on shorter shots due to lack of velocity.
As for a 6mm, only ever had one and wouldn't own another. Problem is the length of the case. Mine was a Mod 700 Remington and due to the length of the magazine I could not load bullet's out to were I wanted them, magazine just to short. On the other hand I'm on I think my third 243 and no problem seating bullets out where I want them. I like the bullet just off the lands and seated to the base of the neck. Using 75gr bullet's in them came about as close at possible to doing just that. Of course for saving pelts the 6mm 75gr bullet is a bit tuff on them! Shooting my present 243 at a paper target taped to a Styrofoam frame at 200 yds, those 75gr V-Max bullets were blowing up going through 1" Styrofoam as witnessed by all the blown up jacket material. I'm not all that sure a heavier bullet would help unless the velocity was greatly lowered. Then of course shooting long becomes a problem. I think if I wanted to sell coyote pelts I'd learn to trap and shoot them with either a 22 RF gun or maybe my Mod 16 S&W with heavy cast bullets in 32 Long.
75gr bullet at 4,000 fps? Where ya gonna get that? And if you do barrel life probably wouldn't be so good but the pelts will take a beating also!