Here is the problem with finishes like BLO on knife handles:
On a piece of furniture, or even a rifle stock, the finish is to protect the wood. It is a layer of cured natural oils and resins built up over the wood to cover it in a transparent layered surface that allows the woodgrain to show through. Wet sanding works the wood dust into the pores and seals the wood, making it look prettier and a bit more moisture resistant. This is a great surface for such items but is somewhat delicate. It can take weeks to build up a properly cured finish this way. Set a cold wet beer bottle on it or a scratch it by accident and you are re-doing the finish. The items that do best with this type of finish are ones that get little surface contact with things, especially wet and dirty things.
On a knife handle the opposite situation exists. The surface should be in contact with your hand almost fully and it will get wet, dirty, and banged up. On a knife you want the finish IN the wood, not ON it. Wet sanding an oil finish in repeatedly, letting it cure, and then sanding it almost completely off the surface will slowly make a durable and attractive handle. Using a more penetrating finish is a better choice than BLO. Using stabilized wood and wet sanding in a finish will make it look like glass and take wear and use even better.
To me personally, I do not like the look of a "varnished" knife handle with many coats of finish built up over the surface. I have never seen one that was used that stayed that way. But when one of my stabilized wood handles, or one with a worked in finish, gets worn by lots of heavy use and washing I simply give it a few strokes with some 800-grit paper and buff it with white/pink compound. It comes right back to a like-new shine. That is because the finish is IN the wood, not ON it.