FTP is the most widely-used solution to save and retrieve files from a remote server. It has been around for decades and it's a fairly easy protocol to use that can deliver good performance as it provides minimal overhead over transferred content, while supporting powerful features, such as transfer recovery.
Often, software needs to receive files automatically uploaded by other software; FTP has been frequently used as a robust solution in these scenarios over the years. Whether your software is the one in need of uploading the content or the one that has to receive it, the Python standard library has support for FTP built-in so we can rely on ftplib to use the FTP protocol.