Board Thread:Questions and Answers/@comment-1026420-20140327170554/@comment-24152851-20140918082110

Ditto's only ability is duplication, and physically he's not much better than Grey Matter. His only advantage is strength in numbers.

While one Echo Echo clone is already quite proficient with his sonic scream, plus the point others keep mentioning of how defeating one Ditto would kill them all, while Echo Echo clones are expendable.