The tools solves an issue that may sound trivial but is a huge loss of time for anyone that needs to create beautiful gradients: not being able to change both colors at the same time. With this tool, I can use both thumbs to change both colors at the same time and preview them in real-time. Much much faster than any desktop design tool (I use Sketch). Thanks you Edouard!
Quick and simple way to make gradients with the tip of your fingers