The casino obviously thinks there is a benefit or they wouldn't pay the guy to do it. Economic or not, who cares? If the guy could get a "better" job, wouldn't he? Do you think there is something immoral about a service job?
We all could fetch our own meals from the kitchen at restaurants. Are we exploiting waitresses by allowing them to serve us? Is it demeaning to demand someone else cook us a meal for money?
The difference between vain and nice is in the bearers heart. Is it vain of me to leave a large tip at a restaurant? If I am doing it to show off how much cash I have, sure it is. If I leave a large tip because the server has worked hard and I appreciate it, it's kindness. If the service is lousy and I leave a large tip, perhaps I do it out of compassion for someone who might be having a hard day?
The vast majority of my experience in the high roller area was with making large payouts to other casino employees to be delivered to the winner (the same is done in low paying slots). The difference between the two areas was vast. In low paying slots the slot crews were rude, and demanding toward me because they were trying to hustle big tips by being fast. They also avoided slot fills like the plague because tips were nonexistent and that job takes time.
In the high roller area I was NEVER pressured to hurry and was treated kindly. The amounts of money were large and everyone was more concerned about accuracy. But also the slot crew could assume they would get a nice tip even if the patron had to wait a bit. I can't recall doing slot fills at the high rollers window, I think the jobs were separated.
The difference between vain and nice is in the bearers heart.
We can't see into Bill Bennett's heart, so we can't know if he was showing off his wealth. I assumed he was, but that's only an assumption based on the amount of money and my generalizations about high rolling. There is also a difference between leaving large tips and high rolling (like the ones I described above).
In the end although we can't see into Bennett's heart, we can say he tested his virtue, and perhaps tempted fate by dropping such large amounts of cash it would be hard not to show off.