It's always easier to learn a language that is well structured and provides features compatible with other popular langauges. This allows people to switch from language to another with minimal fuss.
Here are some of the reasons why Microsoft decided to create it:
Typescript provides a structuring mechanism for code, especially large pieces of code. It does this by adding class based object orientation, interfaces and modules. These inline Typescript with the best industry practices hence allowing for building of large yet maintenable projects.
Typescript adds static type checking at compilation time. This allows us identify various programming constructs that are likely able to lead to errors and correct them. This leads to creation of more reliable code. It also makes the programming as well as learning more intuitive through IDE intellisense support.