BITD, when LF flanges were common on road hubs, and we built with lighter spokes, 4x 36h was common to reduce torsional load on rear wheels, especially for alpine riding. I still build 36h LF track wheels 4x for sprinter clients. Otherwise 3x,4x barely makes a difference either way, especially with SF hubs where the difference is marginal.

There's also a practical advantage to the builder in building 36h 4x. It allows use of the same spokes regardless of flange size, reducing inventory needs.