It's actually fairly common. Almost all of my stationary tools are wired that way. Three are 3-phase based on VFD (all are wired to require a restart), the rest are single phase. I tried to find a picture of typical wiring, but Google is so infected with YT videos, that was futile.
Can you post a link to the datasheet for the contactor you have (or scanned copy of the appropriate page)? In general, both ON and OFF switches are momentary. ON is N.O. and OFF is N.C. The ON activates a relay to start the motor and the relay is held in position by a "keep alive" circuit going through the OFF switch. When power is lost or the OFF switch is activated, that circuit is interrupted, the relay opens, and restart requires an action by the user.