Phillips was designed to be simple to cut and self-centering, so it could be used on assembly lines. It exploded in popularity just as mass manufactured goods were becoming popular purchases.
Later styles like square, Hex (cut) fasteners, or 12-point (both types) or Torx can create higher torque without slipping but are not centering the way Phillips is.
Not only is it self-centering like phillips and JIS (eg the reason they are used in so many line-assembled manufactured goods) but it's has superior contact like a Robertson (square drive) or hex or torx.
The patent is expired and it now has ANSI and ISO standards.