I skimmed the study, and that statistic is a little misleading.
They weren't typing predetermined sentences. They were instructed to come up with a story based on some pictures and write it down. They weren't bottlenecked by typing speed, but rather by pauses for thought between words.
This is why I hate these sorts of "X proven better than Y" posts. In this case, the study is available, so you can call the blogger on his BS. In many cases, the actual study is paywalled or not even linked to, leading to all sorts of misinformation.
They weren't typing predetermined sentences. They were instructed to come up with a story based on some pictures and write it down. They weren't bottlenecked by typing speed, but rather by pauses for thought between words.