I've flown London to Washington DC for meetings and then immediately returned to the airport to fly back, and I'd have loved to have had the ability to fly supersonic for trips like that.

So while "just" flying East might be less attractive, very brief return flights will be attractive even if one of the legs doesn't seem very beneficial.

There are plenty of scenarios cutting hours off will improve. Whether there are enough of them to make Boom profitable is another matter.