With those numbers, I would say that is 30% and that is a lot. With many tax returns, each dollar deduction can possibly equate to a dollar added to your return and money back in your pocket. It all helps.
Anytime you want to pay me an extra $1 so that the government will give you $.30 back, you are welcome to send me a check.
What 'helps' is not paying interest on a luxury purchase at all. If money is so tight that the 30% deduction is the difference between doing it and not, don't do it.