Raspberry Pi backup is what you really need if you work on Raspbian. Believe me, you do! If you иackup your Raspberry Pi SD card in due course, someday it may save your files and your project. Alike any other hardware, the RPi devices may sometimes simply stop working.
It can occur due to a number of reasons: overheating, errors, energy supply issues, cable connection failure… All these problems will make you unplug and plug-in again the device to restart it. And such actions taken repeatedly will certainly lead to spoiling your SD card you are saving your work files to.