Changing credit cards that frequently is bad for your credit, which often costs you more in the long term (e.g. if you ever buy a house). So I'm not sure that's the example you should give-it can come across as pretty short-sighted.
Source: I used to work in a credit cards division at a major bank.
Also, you should at least be charging one thing per credit card so they are still remaining active.
As dumb as it may sound, it is actually better for your credit score if you have around $5-$10 on your statement on any given month which achieves a higher credit score vs. paying it off entirely. This is illogical because most smart people just set it up for auto pay and pay it off entirely. Hope that helps.
I'm curious to see if this strategy is sustainable.