The cutters will deform the surface quicker than vice grips, but run a risk of cutting if you're real strong or using compound cutters.
The hardness of the axle and exactly how it is hardened could have inpact here too. Some methods leave only a hard surface, some deep and some end up brittle; while others might be forged that way.
The vice grips pressure and blunt blades are capable of crushing before cutting is what he's trying to say. You need to determine which method suits your skills; both could work.
Cutting ever so slightly moves surface metal while leaving the core strength.
Parallel to axle is going to give grip against axle spinning in place. Perpendicular is going to prevent pulling off.
(many toy cars use a crosshatch at about 45° for holding wheels on and providing grip during tourqe application. )
JBW will likey hold best, but bearing retainer should allow easier future disassembly. If you can get JBWelded parts seperated, the residues sand/grind off easy. I think a wheel puller might break the bond, but not 100% sure. Heat might help to crack it's bond (with metal expansion).
Regular JBW is slightly stronger than 5minJBW imo.
