I always ask for pajamas, but never wear them on the plane. I use them at home - they are very comfortable and a nice souvenir. And I think the lounges and on-board dining and wines are a big part of the F experience. I wouldn’t skip them.

if you are returning on BA through LHR, ask about the cost to upgrade. It is often only about 600 USD. F checkin and the Concorde Room are pretty nice.