Stamping shears metal. Laser and waterjet cutting leave heat-affected or ablative zones right along the edge. Both processes alter the material exactly where precision matters most.
Photochemical machining works differently.

A photoresist stencil defines the part, and the unwanted metal is dissolved away in a ferric chloride solution rather than sheared or burned off. Result: no burrs, no induced mechanical or thermal stress, no heat-affected zone to account for.

For parts where edge integrity and flatness aren't negotiable (thin-gauge aerospace components, RF shielding, medical instruments) that distinction matters more than most spec sheets let on.