I think of it like this, Craftsmanship is about having the discipline to dot 'i's and cross 't's. It's about scrubbing out the pans after your done cooking a meal, because while you might be able to keep reusing a skillet without cleaning it to produce delicious meal after delicious meal quickly, eventually, you're going to send a customer to the hospital.

Keeping code in small readable chunks that have automated tests makes it easier to maintain and if this hasn't been your experience then I would say you haven't been doing it correctly.