Sanitizing your TT is like chicken soup, it cannot hurt.
We use the camp water if it is available but we carry about a half tank fresh water from home. More than once we have stopped at a campground with really nasty tasting water. That said, our TT water from home comes from a well and I am sure it would make some people choke.
Some folk are very sensitive to the taste of their water, and use bottled water. The fact is, water sitting around in the TT tank in hot weather can taste "old" for lack of a better word.
Draining the water between trips and a dose of bleach during the season seems to do very well for us.
It might be different if we live in the hot sunny south or were sensitive to the taste of water but I still drink from the garden hose.