I just keep the parts well lubed and have no issues with carbon on the bolt or anything else.Before,during and after I put a few drops of CLP in the carrier vents and work the action a couple times.This keeps the carbon on the bolt tail and in the carrier soft.Otherwise the carbon is self limiting.
If I do a high round count with cheap steel cased ammo or similar and have large amounts of carbon/funk I'll soak the bolt...dropped in tail end first...either in a jar of Hoppe's No.9 or CLP overnight,what doesn't fall off the bolt while soaking wipes right off.
But Im all about cleaning tools and an Otis fan,so I understand if folks like the bolt cleaning tools if thats what they want.In fact I have a B.O.N.E. in one of my Otis kits,haven't used it yet though.The bolt tools are not needed if maintenance,and more importantly if the rifle is adequately lubricated before,during and after use no matter how well you clean.