I once did a post that involved regular travel to Middle East, which was all J. The pattern of travel usually involved weekend flights or very disrupted days each way due to the timetables, and J meant I could accept loss of a Sunday, or fly overnight and be in job the next day (e.g. 2am from BAH into LHR at 7, in my office by 8.30 at latest and do full day of work). This was a genuine life saver in terms of my ability to sleep and maintain some semblance of home/life balance as on weekends I wasn't too tired to do anything.
When they moved to a PE policy, I moved on - sorry, but I am not sleeping sitting up and then going to work - that is not sensible or healthy.
A 'no J' policy is also not always cost effective - I always cite example of needing to send team member to Korea, where direct BA flight in PE was approx £4500, while the indirect Emirates flight in J with limo transfer at each end was approx £1700 for a journey that took about 4 hours longer. A total no brainer, but one hell of a fight to get it sorted!