Gist is that tongue cleaning yields less bacteria (that's one major cause of bad breath), but they still recommend both brushing and tongue cleaning since the reduction of tongue bacteria didn't reduce plaque. I never claimed that it did though.

Tongue scrapers are cheap and awesome. It's amazing what kind of disgusting stuff you'll scrape off that thing. I'll nearly guarantee you better breath unless you have some serious other problems, like periodontitis.

A second source on elderly: https://www.ncbi.nlm.nih.gov/pubmed/16677187

"These results suggest that tongue care is essential for preventing oral disease and needs to be part of any oral care programme in elderly people."