What is your reasoning? Its a variation of the same engine that IW use, and Treyarch's previous CoD BR Blackout ran OK.
They've already stated publicly the intention is to have Warzone coexisting as a link between future CoD titles some time ago.
Warzone runs on the same engine as current COD. BO will run on a different engine. Warzone will continue to exist on the COD engine and they are not linked at all. The character movement and guns including attachments are all different from COD
Basically if you unlock a gun or skin in BO that you can use in warzone it will have to be ported and created in that engine / environment.
Completely separate mechanism.