No need for toilet bowl brush ?

Hi there,

Hope you don' find this idea silly . I was planning to buy a toilet bowl brush for the RV then I came across this idea . Instead of throwing the toilet chemical drop-in directly into the tank, I throw it into the toilet bowl while the toilet seal is closed . I add water and keep the chemical and water in the bowl for about 10 minutes then I open the seal to let water into the tank . The bowl is shine and clean .

Here are my concerns:

1. Will the chemical damage the toilet seal if it stays in the bowl for too long ?
2. Is it safe (any health concerns) ?

thanks