The 30k is the kicker for me. Don't normally spend that much but if the right expenses came through at the same time I could pull it off.
A few years back I did one that needed 10K spend in 3 months to get $1000 back.  I timed it to align with farm insurance renewal, then hit all the vehicle policies, prepaid the entire years health insurance premiums.  Even bit the bullet and paid 3% at coop on feed bill to hit the limit and get the bonus.

I am going to look at getting the Capital One in April as we run a lot thru the business card in the summer and have the cashflow to pay it off monthly then.