It is subject to plugging which then negates the pressure communication and the functioning of the main valve which generates the pressure pulse. The second issue is the limitation to how rapidly the solenoid can be fired with the limits put on the system by its power supply, typically batteries. The valving mechanism can only be fired as rapidly as the capacitors can be charged delivering the power to the solenoid.
In addition the issue of plugging with the rotary main valve pulser is eliminated since the signaling valve is a poppet orifice not a rotary valve which when closed to generate its positive pulse signal creates very small restrictions around the rotor stator elements. It is during this phase that a rotary pulser design is very susceptible to plugging and jamming as the entire flow of the mud through the drill string (and the rotary signaling valve) must pass this restricted area.Stepper motor control forces act to lock the valve and increase as the flow area in the closed position becomes restricted with debris and the pressure increases. On the other hand a poppet orifice linear pulser in the same pressure pulse generation stage does not have the same locking forces applied due to its geometry. In some arrangements it the forces would actually force the valve open.
