Do they have any plans for mobile apps?
They do. The web-based clients work fairly proficiently on mobile web browsers for now.
i don't really think anyone but businesses use email nowadays. i only use mine to sign up for forums and websites.
How about when those websites are jerks and send your password in your activation email? Ever realize that Google
scans your emails to find out what to advertise to you? Did you also know that Google occasionally
gets hacked and your information (and possibly emails containing your passwords!) are
leaked?
Having appropriate security and restricted access to your own personal information is actually a very serious matter.