Why should I use Netlify Functions?
Netlify is a website hosting service, but it only hosts our front-end, while our back-end must be hosted anywhere else. And that usually is what you do, but if I'm just planning to build a small project that would be like filling a cup of water with an ocean, there is no need for that.
Netlify Functions comes to solve this problem, you can keep your back and front-end together by using Functions that can be called just like a back-end api. And it makes the code easier to edit since it's all in one folder.