Not about the money at all. If you can buy expertise and solve the problem, then it’s not a problem.Why should they not take any intel they can get?
Chinese panels would assess the info and determine what is useful and what isn't.
I strongly doubt the cost of hiring some disgruntled ex servicemen to provide their feedback is a signficant economical challenge for the world's largest economy lol
Since its effectively free, you shouldn't look a gift horse in the mouth.
But this is similar to when Ex-RAF pilots were hired to train Chinese pilots. During the entirety of that program, UK maintained constant contacts with these pilots. What do you think their regular debriefs were about. Sure werent mabout Chinese cuisine or sightseeing.