Polyphenols are good for you. They function as anti-oxidants.
Tea is good for your teeth, too. You can drink the fluorides in it, without the guilt of being harangued by an anti-fluoride campaigner.
Tea, along with a Bex, is relaxing. It originated the expression " a cup of tea, a Bex, and a good lie down" to denote someone who should really take a timeout from the stress in their life.
Conversely, ever noticed how people get wired on coffee? IMO the Boston Tea Party set America on an irreversible path of angst, which seems to be getting worse.