Because you can enter things like I have an AT&T go phone how do I refill it? and actually get the website you want so you don't have to go digging through your unsearchable student email account looking for the email your mother sent you the last time you wanted to refill your phone's minutes.
Of course, Google cannot tell you answers to questions like Does my mother want me to use the debit card or the credit card? I forget. So you'll have to dig through your emails anyway.
And then after you've determined that you in fact want to use the debit card you will find your wallet and remember that you don't even have a credit card anymore--not because you abused your credit-card privileges, mind you (you are a good person and have never made an unauthorized credit card purchase that would damage your parents' credit--not only because you are a good and obedient daughter but because they are paying for your college and you know what side your bread's buttered on) but because the credit card company did something stupid so now We Don't Like Them Anymore and you could carry the nice shiny credit card around if you wanted to but it wouldn't do you any good because the account no longer exists.
If that was you doing all that, you would now need to stop blogging and go do homework.