I have been doing more or less the same with Amex for many years. It is the only credit card we have and has to be paid off at the end of the month. I use it for everything I can and then pay them with my banks online payment service once a week. We get points for every dollar spent and have taken a few very nice ‘free’ vacations.
I was behind a couple in Sam’s once as they bought a HUGE flat screen tv (this was a few years back when they were first coming onto the market) - I overheard them telling the cashier that they were buying it with either points or cash back or something from their Credit Card - they said they even paid their mortgage on the card then wrote one check for all monthly bills to Discover I think it was.... I have to admit I was pretty stunned.