I believe that this is partially because default shells (mostly bash) are not 'really' beginner friendly, and you usually need to spend some time configuring them to be comfortable working with them. That said, i use fish shell so what do I know :)
Terminal is just the program that shows text. New terminal emulators (not all new terminal emulators, but the ones mentioned in comments, the ones op asked about mostly) are way more than just programs showing text, they are also replacing/re-imagining the shell, or re-imagining the way you interact with the shell; thay are wrappers around the shell (and more).