The reference was made to people going TDY=Temporary assignment. NOT permanent party.
TDY are usually there for less than 6 months and are paid per diem and such which is supposed to cover living expenses MANY times the allocation does not cover all of the expenses so by staying in Famcamp the member might very well be keeping closer to actual allowances. Sure, there may be instances where the member gets to pocket some of the extra but that is usually overshadowed by the extra expense of being TDY.
Besides that, when the member returns to home station they are required to fill out a travel voucher and submit receipts anyway so it is possible that even though the authorization might be for a specific amount, if the member did not spend that much or does not have receipts for that much they may very well not get paid the full authorized amount.
The last TDY I went on before I retired I was not given sufficient reimbursement to cover all the costs and had to go out of pocket a few bucks even though I was authorized more.
Then there was the BOA Govt Credit card ripoff where BOA charged me something like 20% interest rate from the date of purchase and Uncle Sammy took his own sweet time doling out the cash. I had to make the first two months minimum payment out of pocket on my own before I received the reimbursement. THEN I had racked up interest charges that Uncle Sammy DID NOT reimburse I had to complain at the finance office.
After having a BOA Government travel card I decided I would NEVER do business with BOA on my own!