A friend (in USA) with a 220v, 1-phase horizontal bandsaw in his home machine
shop wants to replace the 1/4 hp motor with 1/2 hp and rewire with an
auto-off switch (when the blade cuts through the metal).

I always default to using a 3-wire control with contactor, but he asks the
logical question: "Why?"

Other than the "If the power fails while cutting" answer (which he says seems
of limited additional value on a saw with auto-stop feature) I wasn't very
convincing.

What are the arguments for using a contactor as opposed to a simple on-off
switch of equivalent rating?

Thanks.