An electromechanical or coaxial switch can be preferable when the project prioritizes low insertion loss, high isolation, broadband behavior or a physically open contact state and can accept slower switching, finite contact life, size and coil or actuator control. A solid-state or PIN-diode switch can be preferable when fast switching, high cycle count, compact integration or silent operation dominates.
These are conditional tendencies, not guarantees. Compare the actual continuous band, loss and isolation at temperature, CW and pulse power, hot-switch limit, linearity, off-port behavior, transition time, RF settling, control bias, leakage current, vibration and expected cycles. MEMS and waveguide technologies add other trade spaces.
Do not choose by technology name. Supply the route states, waveform, switching frequency, power during transition, lifetime target and mechanical boundary, then require evidence under those conditions.