BA crew on one of my flights last week jokingly asked a mask wearing passenger if he was contagious before telling him that the mask he was wearing was pointless.
I was coming back from 5 weeks travelling around South East Asia and on every airline I used the staff wore masks, apart from BA.
I certainly didn’t feel the need to wear one. Good and regular hand washing is key. I had some hand sanitiser for when that wasn’t always easy out and about.