Unfortunately that's wholly true. I've never been asked to see certificates for any qualification, or any university work written work. It's the creative stuff in your portfolio, and later, the experience on your CV that count.Don't worry too much about it though. Nobody ever asked to see it, or what mark I got in my course. Your portfolio is the most important thing.
That's also true. And if you enjoy the dissertation, so much the better. It takes a long time to do so you may as well get something out of it.Saying that though, education is of course worth doing. It's hard to get a design job without a degree (or equivalent) in design (or a related field) and one day someone might bother to check - it wouldn't be good to find out someone hadn't done what they claim.