If that’s what you think how bout the other way around? How can you evaluate content without design? No typography, no colors, no layout, no styles, all those things that convey the important signals that go beyond the mere textual, hierarchies of information, weight, emphasis, oblique stresses, priorities, all those subtle cues that also have visual and emotional appeal to the reader. Rigid proponents of content strategy may shun the use of dummy copy but then designers might want to ask them to provide style sheets with the copy decks they supply that are in tune with the design direction they require.
Typographers of yore didn't come up with the concept of dummy copy because people thought that content is inconsequential window