Should I buy a breast pump bag?

My insurance covers a breast pump, so I'm going with the Medela one. It's the same pump that they sell at the store with the bag, and cooler, except, mine will not come with a bag. I'm fine with that since I am not partial to the way the bags look anyway. My question is, will it make life easier to have a pump bag? I found one on sale, and it is gorgeous. It says I don't have to take everything apart. However, I also have one too many diaper bags...so I don't know...I could use one. I just don't want to have a jumbled mess. The pump bag is down to 69.99 from 129.99. My husband said I could buy it. I bought $150 worth of stuff from Babies r us on his credit card, and I was going to pay it, but he said I could just deduct the price from what I owe on the card. I just feel irresponsible if I do that, even though it's not like we are drowning in credit card debt or anything. What do you think?