I've read up on the info about my credit card it says that it allows me to get free checked bags.

However a year ago I traveled on United using my United points (UR points from chase that got transferred) and still received free checked bags the whole trip.

Hence do I really need to pay with my United Mileageplus business card to get the free checked bags? I haven't paid for my next flight yet as it's on Farelock. However, the current reservation say that I would owe 25$ for the first bag and 35$ for a second bag. Would this become free checked bags like my last flight if I pay the price of 45k miles and $86 in fees with a random credit card? Or does it need to be Mileageplus?

I'd prefer not to pay with the Mileageplus credit card because I have a Barclay Arrival + with tons of points that I can use to get a statement credit on any travel related purchases.