The EOS account names can easily be used like the Steem ones as well as every other dApp deployed on the main net. Think of it as a global twitter handle across all dApps.
Rather than quote a public key when your friend want's to reimburse you for pizza night you can just give him your account name. He can then look up your high score on Space Invaders and beat it.
Your account name can be tied to your identity and reputation, should you meet a new person, rather than give them a business card you can quote your EOS account name and they'll be able to reach you across all different kinds of social media all with the one account name.
Should you get EOS based Ubers, and then get on the Lyft network, drivers will be able to see your reputation based on the account name.
Sub names like
john.google.com could be invaluable when trying to tell if someone really represents that company or is trying to impersonate them as well. So an easily recognisable account name for companies will be invaluable for public recognition.
E.g. If I see a smart contract that promises X and it's signed and deployed by
Google then I won't question it as much compared to it being deployed by