I believe the main barrier for using reusable bottles and tap water for many people is the accessibility they have to it. I know that when I go to Mexico with my family, we cannot drink tap water, and its very uncommon to see water fountains where you can easily refill your reusable water bottle, so plastic bottles are more commonly used. But that is a more world-scale issue, in a smaller-scale issue, a lot of people don't like the taste of tap water, and my simple solution to that is simply adding some flavoring, either store-bought or homemade such as lemons and berries. Thankfully, I have accessibility in the U.S. to drink tap water and to easily refill my reusable water bottle in many places, so keeping up this habit won't be a struggle, in fact, it is already a set part of my daily routine.