1] It reduces ckt complexity and cost.
2] We can implement many combinations logic ckts using multiplexer.
3] It does not need K-maps and simplification.
4] On the advance level the ability of MUX to switch directed s/g can be extended to smter video. s/g, audio s/g, etc.
1] Added delays in switching ports.
2] Limitations on which ports can be used simultaneously.
3] Extra IO many require to control multiplexer.
4] Added delays in I/O signals propagating through the multiplexer.