Actually hand creams and moisturizers seal in any moisture that is on the surface of the skin - that's how they work. Women will find that if they apply these products after showering or bathing, then they get better results - but that's counterproductive for what you need.
Oils don't make the skin soft - it's keeping the cells saturated with water that keeps them plump (youthful) and smooth (full of water to fill in the valleys and bumps). If you lock the water in, then the skin looks and feels softer and younger - but it has very little good effect if you're interested in keeping your calluses.
Since calluses are really dried and dead surface skin cells, it doesn't make too much sense to now wet them or lock moisture IN them/under them, and decreasing their dryness if you are trying to preserve them.
Calluses are the body's natural defense to abrasive and aggravating condition and it's just trying to put up a protective sheila for the living cells underneath. Anything that moisturizes them by holding water locked under a film of oil isn't conducive to keeping them as you want - dry and hard.
I remember an interview with SRV's bassist and he said that Stevie used super glue to reattach his calluses when they got ripped off. If SRV needed calluses, then it's prolly a pretty good idea to keep yours high, dry and un-softened with emollients and products to remove and repair your skin.
If you need to toughen skin, then the old longshoreman's trick was to soak their hands in brine (very salty water) to harden, dry and toughen them. Keeping them wet with emollients makes the skin soft and actually weaker.
Unless it's just the fragrance ---- or the frilly pink and baby blue bottles.
