why is paying online donations with a credit card a bad financial planning?

I dont get it, someone just told me this. what financial plan? I donated some money and next month I’ll pay for the credit card from my account (well the bank will automatically do this).

Do you pay the entire balance before the end of the grace period? Do you know exactly what the grace period is for your card?

If you carry this balance on the card then you are going to be paying interest on it. That will undermine any tax write off you could hope to gain. If you are not wanting to report this on your taxes but are rather just giving from the heart then the interest you pay on this balance will just be money thrown away.

I would not trust the bank to automatically pay off the balance before the end of the grace period. I would keep an eye on that if I were you.