That depends on the language. Big Java codebases are very hard to develop without good IDE, because good IDE can make a lot of problems with some language go away. With Java, this is mostly about syntax checking and incremental builds, code generation, packaging and suggestion of classes, methods and data types.
Python doesn't really have problems similar to Java, so Java-style IDE doesn't seem necessary, while the language design makes some of the best features of Java-style IDEs hard to implement (but my last experience with similar IDEs was few years ago, so that might be fixed problem).
Now, the problems with python (concurrency and general slowness) are impossible to fix with IDE, so they might not be necessary. Still, IDEs are _integrated_ and thus allow you to set up development environment quickly and efficiently -- think about what if you moved to different computer, or even to different platform? Your shell scripts might not survive that, but IDE would. And being integrated has other advantages -- yes, any developer can (and should be able to) use git directly from command line. But editor that shows you which lines have changed since last commit, and who edited this part of file and when is useful. You can do that with git from terminal, but just seeing the former in editor, and getting the latter just by moving the mouse to the right spot can be helpful.
Of course, lot of the things IDEs do are about team cooperation, and won't really help single developer.
Python doesn't really have problems similar to Java, so Java-style IDE doesn't seem necessary, while the language design makes some of the best features of Java-style IDEs hard to implement (but my last experience with similar IDEs was few years ago, so that might be fixed problem).
Now, the problems with python (concurrency and general slowness) are impossible to fix with IDE, so they might not be necessary. Still, IDEs are _integrated_ and thus allow you to set up development environment quickly and efficiently -- think about what if you moved to different computer, or even to different platform? Your shell scripts might not survive that, but IDE would. And being integrated has other advantages -- yes, any developer can (and should be able to) use git directly from command line. But editor that shows you which lines have changed since last commit, and who edited this part of file and when is useful. You can do that with git from terminal, but just seeing the former in editor, and getting the latter just by moving the mouse to the right spot can be helpful.
Of course, lot of the things IDEs do are about team cooperation, and won't really help single developer.