Well it really depends on the size of the project. For small project I agree but for larger projects Typescript really helps to produce better and more robust code (and also faster if it's well integrated into the editor like VS Code). I am currently rewriting a Firefox Extension in Typescript that started as a simple script and grew in complexity (quite a bit) to make it easier for others to contribute (it's open source) and understand the code and I wish I had started that way, it would have saved me quite a bit of work by now.