I wouldn't say there are necessarily advantages or disadvantages - rather differences. Notwithstanding, there isn't much Neapolitan about using WMLM. Basically it's personal preference: different appearance, texture, flavor, contribution to the overall wettness of the pie, etc. There are a couple pies where I like the WMLM from time to time, but in general I prefer fresh. For WMLM, I never use shredded - only thin slices.
One advantage of LM mozz vs fresh in general is that the quality of LM will be much more consistent.