It depends on the orbit, the function, sensors, and the size of the satellite.
If you want to go to an L2 orbit with a 10,000 Kg satellite with one of a kind sensors (relatively speaking) for earth observations, disposable doesn't make sense.
Low earth orbits with low weight satellites, pico/nano/micro/femtos - cheap disposable constellations with mass produced widgets make sense, particularly when you can launch them on another mission.
If you want to go to an L2 orbit with a 10,000 Kg satellite with one of a kind sensors (relatively speaking) for earth observations, disposable doesn't make sense.
Low earth orbits with low weight satellites, pico/nano/micro/femtos - cheap disposable constellations with mass produced widgets make sense, particularly when you can launch them on another mission.