[lucasoshiro]

Another point not mentioned by the other comments: you run code interactively (like you would do in a REPL), but keeping what you wrote. This is very practical, for example, if you want to develop a simple code for data analysis. You fetch the data only once, then develop the rest of the code based on it, instead of writing everything without seeing the data.

As a consequence of it, it makes easier to write bad code. I care about code quality, but I must admit that sometimes I needed to stop and refactor my jupyter notebooks.

It's a nice tool, but it doesn't replace writing a .py