There's a reason why double-wall vacuum insulated bottles are so popular today. The reason is simple enough...they work!
Suppose you have a non-insulated water bottle in your car and have it filled up with water and ice. It's a hot summer day, and you head into the grocery store for an hour. You come out and want a drink, but your water isn't exactly refreshing. All the ice is gone already! Not the end of the world, but it sure would have been nice to have a refreshing, cool drink on hand.
Now suppose you had a double-wall vacuum insulated bottle and did the same thing. You'd come back to a bottle that had cold, refreshing water that hadn't warmed up nearly at all! There's a reason that Hydro Flask has the motto "Unexpected Refreshment." When all you've used your whole life are non-insulated bottles, it can be hard to believe that you have a cool drink to enjoy after so many hours.
The same goes for hot drinks. If you like using your insulated bottle for coffee or tea, it'll keep it super hot for hours. So hot, that you'll need to be careful when drinking it later! There's no shortage of stories from unsuspecting people who assume their drink has cooled off after half a day, but when they go to take a chug of their morning coffee in the afternoon, it's still hot enough to burn them! It's a lesson you'll only need to experience once to learn (or better yet, just remember this post and avoid it all-together)!
So take advantage of this technology! Whether you like your drink hot or cold, you'll be able to keep it at the ideal temperature for many hours longer. It'll bring you that unexpected refreshment when you need it most!