Reasons for using "real-world-domain" on e-smith:
1. If we do not, all our e-mails will be rejected by provider (for relay-control) or will get "me.local.net" as sender-adress; this will make it complicated to reply

2. I am using (on one site) and am planning (at office site) to use full dyndns-support with our permanent adsl-connection. So i want to host my sites on my server fully and just transfer the outside domain and mail to my own server. This makes it easier to administer for me.
3. On some more heavy-traffic sites i am planning, i still want to use my outside webspace for performance reasons. Our upload speed is just 256 kbits, so dyndns will not work with heavy traffic.