Discussing a money strategy with 0% APR card and HYSA account What could go wrong

You get used to spending about 5% more on average.

This is pretty common practice here But honestly, I don’t think the return is worth it unless I’m getting a bonus on a card I won’t be using otherwise.

Also, the appeal of this strategy will drop as soon as interest rates go back down.

Aside from taxes on the HYSA earnings, I don’t see any major issues here.