Greeking or Jabberwocky or "lorum ipsum" as you called it, is invaluable for a designer. It allows you to fill the space where copy is supposed to be, without having to take all the time to actually come up with it yourself.

If you're working on a website for a client, you just want to establish the style for the website for them. Odds are, you won't be the copywriter either (and if you are, you'd better charge more for that as well).

Plus, let's say you come up with a concept for the website for the client. You include all of your own text, text that you came up with yourself that probably took an hour or more to write. You send the client your proposal, doesn't like your design, but then takes everything that you've written in your concept. He's basically stealing a service from you. And you're wasting time (and time is money in this business.)

My advice as a pro: use jabberwocky.