It was just an example. Maybe you have your private key locally to access your email, so that if there is a security breach it's impossible for them to release unencrypted emails?
I mean I don't know why, but there are loads of good examples of why someone would.
I haven't checked in a year or so but back then Moore's law was still in action so it'll only become cheaper and cheaper (and be less hard on the environment I hope) year over year.
Bgrlgrb brglbub (cannot talk, lips too big)
BgRrlbub!