It's a bit of a straw man there. The NYC street grid system was meant "to unite regularity and order with the public convenience and benefit and in particular to promote the health of the City ... [by allowing] a free and abundant circulation of air". ("Foul air" was thought to cause disease.)

Salt Lake City grid system was also not designed for tourists. It was designed for travelers, yes, and I believe it was part of the vision that SLC would be looked at as a model city, with a strong Cartesian/classical influence. According to Wikipedia, "In these western cities the streets were numbered even more carefully than in the east to suggest future prosperity and metropolitan status."

Also, a grid system made it easier to subdivide the land which was newly part of the US.

So to say that the grid system is influenced by tourists is a bit of an exaggeration.