It’s silly really , I know of 2 UK airlines that still do this procedure.
1. It basically says they don’t trust you on your own
2. Lots of the cabin crew put in the flight deck are very junior and have only just passed a security clearance (if at all….)
3. God forbid it happened again ! But do you really think a young 18 year old would stop a 200lb extremist.
a chilling thought but interesting