I have flown Business Class once and then on a miles ticket, but all the miles earned to reach that point I paid for myself. I was on Business Class as I needed to get home on that flight and there were no Economy seats left.
I was surprised to find a load of people in Business Class who worked for NGOs and Charities and were on a relatively short flight of 4 hours. Surely they could have 'coped' in economy?
Those charities no longer receive donations from me.