There are some theoretical advantages, but mostly I think it's aesthetics and "gee wizz" factor at least in folding knives.
You could gain some stain resistance, but there are some really good stain resistant steels out there now. You can gain some flex instead of snapping a blade, but how many people are snapping folding knife blades under even abusive use, even with steels not known for impact resistance, on larger fixed blades I could see it being a real factor. You can perhaps save some super steel material, but the cost of lamination, QC etc. would seem to offset any gain in that.
There's also the heat treat trade off, I believe it was stated by ZT the reason the 0560CBCF S110v was ran so soft (RC 59) was that to heat treat it any higher would damage the copper brazing used for lamination, so the lamination limited the heat treat hardness, where most users of a folding knife paying for S110v would probably prefer it harder than RC 59 if given the choice.
You could gain some stain resistance, but there are some really good stain resistant steels out there now. You can gain some flex instead of snapping a blade, but how many people are snapping folding knife blades under even abusive use, even with steels not known for impact resistance, on larger fixed blades I could see it being a real factor. You can perhaps save some super steel material, but the cost of lamination, QC etc. would seem to offset any gain in that.
There's also the heat treat trade off, I believe it was stated by ZT the reason the 0560CBCF S110v was ran so soft (RC 59) was that to heat treat it any higher would damage the copper brazing used for lamination, so the lamination limited the heat treat hardness, where most users of a folding knife paying for S110v would probably prefer it harder than RC 59 if given the choice.