Eric has a good point. True Damascus is actually wootz, which is a kind of crucible steel with a very clear Ultra HiGh Carbon steel showing a dendrictic structure. Very different animal to 'damascus that we think of, which is actually pattern welded steel ( show pattern based on teh chemical differences of mechanially combined ferrous metals)
There is truth in the different wear rate of the steels in the blade, which yes they would provide a more serrated blade, but would be a relative saw compared to the micro-striations left by sharpening). There is absulutely no advantage in using a blade of differnet steels. In fact for a using knife I would rather have a single piece of steel, since between each layer is a potential flaw.Yes baldesmiths and steel producers are going ot try and get a blade with no flaws, but sh*t happens and you can't be 100% certain (except in the mass priduced powder metallurgy stuff).
With modern tool steels there is no benefit to a 'damascus' blade. It was orignially used to combine the strength of iron with the edge holding of steel without the problems each had in older methods of metal production. The ONLY reason for using a damascus blade today is for teh aesthetic qualities of it (and as a maker to show off that you can make damascus, if you buy it then there is no benefit except the price tag associated with the extra work and prettyness)