Q: Why do I need a "3.3V USB <-> Serial module"?

[MrEmanuel]

I'm just about to start learning embedded programming and choose Rust as it seem to be "the future". I have the F3 board but I'm still waiting for the USB to serial module to be delivered. I'm a bit confused as to why I need the module at all? The F3 board does have two usb inputs. One labeled "USB ST-LINK" and one labeled "USB USER". What will the additional usb<-> serial module give me that I can't get from these connections? Thank you! :)

[chirping78]

Usually there are three ways to log something from your F3: 1, semihosting 2, uart <-- this one 3, itm you need the "USB <-> Serial module" to do the 2nd one