It keeps fluoride in your saliva. Which toothpaste cannot do.
I know this is posed as a positive, but I have a feeling in 1000 years we are going to be laughed at like the Romans for putting lead in their wine.
Anyway, my dentist told me to leave the fluoride on my teeth for a few minutes. Wonder if that is more dangerous due to the concentration.
Which is why you're not supposed to rinse the toothpaste you used to brush your teeth.
It keeps fluoride in your saliva. Which toothpaste cannot do.