I use Yahoo Mail at home. My work locks us out of internet mail, among many other things. Not too much of a problem as I understand I am being paid to work and not to read my personal emails. I get it.
However, imagine this...
Life gets ahold of you and you forget to pay a bill and you need to pay it before end of business that day. Then you go to log into the site to pay the bill and you can't seem to remember your password. The only way for you to retrieve your password is to have them email it to you... Now, how is that going to work when you don't have access your your home email account? Son of a gun!
Well, my Yahoo Mail App is even easier because it keeps me logged in and I don't get annoying alerts everytime I get a new email. I just check my mail when I feel like it.