Comment by selfhoster11

> It does a lot of things, none of which very well. And the one thing that I want it to do, it doesn't. Not reliable or not at all. (...) A python script, A proprietary Kobo app over wine, some bash scripts and a well kept directory achieves this. But calibre doesn't.

I prefer to have an all-in-one application that does all this for me. My ebook workflow is not particularly demanding, so I let Calibre manage everything and don't maintain my own scripts.

Such a definition of "job not well defined" is just "IDE, but for ebooks" when seen from a different angles. People swear by IDEs for all kinds of reasons, convienience and integration first and foremost. You may not need an IDE, but I'll take it over rolling my own tools any day.