Keyword: Reusable and fresh
You don't know how nice it is to have your drink as cold or as warm as you left it a few sips ago, or even after a whole day, until you have your Chilly. After you know... any cup or any other recipient used, won't be as good. For example in the morning when all you want is a sip of water but don't want to get up for it, you reach to your bedside, and drink from your Chilly bottle and it is exactly as you poured it. No, it's not like the water you put in a cup and gets the taste of old... :)
Series 2 is here and design wise, they crushed it. Good luck with choosing.