Sure a bathroom remodel can be luxurious without granite slab countertop, it just takes a lot more work - and probably more money than going with granite slab. The breakdown of the contractors estimate for this part of the project, allocated only $150 for the slab.
A cabinet of this small size could be tiled for only a few bucks worth of tile plus labor. In the grand scheme of things, and considering the enormous cost of bathroom remodeling overall, a measly $150 for granite slab countertop wins the biggest bang-for-your-buck award.