Folders vs. tags? - eviltoast

I’m just starting to move over to thunderbird and don’t fully understand the differences between tags and folders or why both exist. I’m using gmail at the moment, and am aware that thunderbird’s folders are what correspond to gmail’s labels. Is there any point to using tags at all? Practical differences/benefits in the way they present themselves as compared to emails sorted into folders? Any use case for both tags and folders concurrently?