I don’t think it’s such a bad investment travelling J (Business Class) especially overnight if it means you can sleep, arrive refreshed and be on top form to able to do business/make a sale.
It is, after all, these sales which keep people in work.
If there is a business case which can justify an extra day of valuable charge out or sales time, there is a case for flying J. If it allows you to get some work done (and not just looking at the AVOD for nine hours!) then it does make sense to pay a little more for that ability to be productive.
F is harder to justify unless your airline of choice does not offer a fully flat bed in their business cabin.
Most corporate deals are giving away longhaul J right now, so the cost of this apparent luxury may only be a little more than would be the case for a flexible economy ticket.
Premium travel costs are not as cut and dried as may first appear to be the case.