It's nice to have more effort put into making sure the DE and default apps work well together. Sure it's possible to start with the normal or minimal Ubuntu ins

It's nice to have more effort put into making sure the DE and default apps work well together. Sure it's possible to start with the normal or minimal Ubuntu install and put something together yourself, but little incompatible things can easily cause "death by a thousand cuts" and make someone decide that e.g. KDE just doesn't work well with Ubuntu. Default configuration counts for a lot.