Why is waterproof mascara important?

Because it actually allows people who are expected to get wet an opportunity to still look good no matter how wet they seem to get.
Usually, the people who use this are athletes like swimmers, brides on their wedding day and etc who are expected to get wet or tear up during the occasion itself. Of course who would want her make up ruined on her big day right?
Waterproof
mascaras are not water- soluble. This means that no matter how much they get
wet, they will not run compared to regular mascaras. Although this wonderful
product is very much practical, try to limit the use as occasionally as
possible.
Why do you ask should you do this? Because mascaras tend to dry out the eye lashes itself. And to get it out takes a longer process.
An oil based solution is used to dissolve the mascara instead of the regular make up remover you already have. Just use this when you have got a big occasion and you know there is a chance you might shed tears.
Contact lense wearers are also a good
candidate to use waterproof mascaras because it prevent the build up from
flaking and getting into your eyes.