Yes, Thyristor is a DC switch.
Description : How is a thyristor used to convert AC to DC?
Description : The device which allows reverse power flow and withstands highest switch frequency is (A) GTO (B) MOSFET (C) IGBT (D) Inverter grade SCR
Answer : The device which allows reverse power flow and withstands highest switch frequency is MOSFET
Answer : Yes, SCR is a unidirectional switch.
Description : What are the desirable characteristics of ideal switch?
Answer : Desirable characteristics of the ideal switch: It is desirable to have power switches characteristics closer to ideal switch. The ideal switch should have the following characteristics. Zero resistance when ... . 100% efficiency. Able to control power flow with zero power dissipation.
Answer : Because it has a higher switching frequency and heat tolerance.