They tend to be known outside of Canada as "square drive" screws. They can't cam out, are nearly impossible to strip in normal use, and will stay on the driver tip without assistance in almost any attitude other than straight down. They're the darling of woodworkers even in the United States of Phillips.

The American bias towards towards the Phillips screwdriver has mostly to do with the gift of patent made to the government in order to support the war effort, putting them effectively into the public domain. They were better than flat screws/drivers, but that's not saying much: when I worked in aircraft maintenance, about half of all of the Phillips-head captive fasteners (Camlock or Dzus type) on inspection and access panels needed to be replaced between periodic (400-hour) major inspections due to stripped heads.

Well, they're good for the same reason that hex/Torx is, and I think most people have a set or two of those.