The Concorde interior was pretty similar to the first class seating of the era (maybe a bit tighter), i.e. more like today's conventional domestic business/first than Polaris lie-flat seats (much less the mini-cabins airlines like Emirates have available).
1. Communication was not as instantaneous as today and more things required face to face meetings.
2. You could basically walk onto an air plane with minimal security interference.
My dad said he flew the Concorde several times from Europe to NYC for business in the late 70s and early 80's and he said it was worth it in that context.
I should ask him how comfortable it was next time I see him. I've been inside of a Concorde that was turned into a museum piece and it is a pretty cramped airframe. I dunno how modern 2020 people would feel about the compactness.