"People" are also sloppy about how they use the term "cloud", yet the world goes on with that concept in hand applying it to everything in site, often times in irritating ways. "Blockchain" is now a thing people can hold in their hand as a way to visualize the concept of a nearly immutable data store. That idea of storing something in an immutable way represents a shift in the way we can think about system's design. Calling it a "Merkle DAG" isn't going to kick off that insight any better than using "blockchain", but remembering what it really is and drawing the distinction with the right people can be immensely useful when trying to implement the insight.