After using this I'm even more confused. For what I spend in a month, there is zero upside to using it for rent: if this calculator is correct, every $100 of the first $800 I spend on rent reduces the net value by $10. I thought this was supposed to be suited towards paying rent, not towards not paying rent!

In fact, with the $495/year Palladium card, all you need to break even is $50/mo on travel. If this calculator is correct, I find it hard to believe that would pencil out for Column N.A. considering I'd be getting $600/year in annual credits. Assuming there's no monthly spend requirement past the initial $4k in 3 months and I can just get the rewards with one month of purchasing thereafter, all I need to do is buy 6 month-long transit passes and I'm already up $155 for the year (ignoring the $1400 welcome bonus since I'd need to spend $4k to get it).

It seems like a great deal (half a year of free transit passes every year) but surely there's a gotcha somewhere in the fine print.