My take on this is going to be short and sweet. We all have our ways of doing things and that’s fine. One of the first things we learn as brewers is to clean and sanitize. However, after a few brews and a general comfort with the process, we all begin to examine the question; does this really matter?
The sort answer is “yes, next question”. “Why?” do you ask? Because while in all likelihood you could brew in a total germ infested hellhole with no cleaning or sanitizing and have beer come out on the other end 9 times out of 10. However, that one time out of ten that your precious brew is spoiled sucks so much that it’s worth the hassle of cleaning and sanitizing.
That’s it, plain and simple.