It sticks and coats. Everything else runs off.
Think of the biofilm on your tongue like grease baked onto a pan. Mouthwash splashes water on it and runs off in 30 seconds. A scraper takes off the layer you can see, and the bacteria underneath rebuild by lunch. Chlorophyll pills and probiotic capsules skip the pan entirely.
A gel doesn't rinse, scrape or skip. It clings — coating your tongue, the back of your throat and your upper gut in one pass, and it's still there hours later.