Comint mode is a package that defines a general command-interpreter-in-a-buffer. The idea is that you can build specific process-in-a-buffer modes on top of comint mode – e.g., lisp, shell, scheme, T, soar, …. This way, all these specific packages share a common base functionality, and a common set of bindings, which makes them easier to use (and saves code, implementation time, etc., etc.).
