I have very little experience in web development, so this may be a very basic question.
It\'s just, from the limited experience I do have (
It can be annoying when I am trying to look at the source to see where a div or style may be missing. I always try to generate any html with a decent layout because 9/10 it would be me that would have to look for bugs.
So, from my point of view it does matter, even if it is not number one priority it should come in as priority 2 or at the very least 3, in my opinion of course.
Nowadays, as a C# developer, I usually copy the source code to Visual Studio and do a ctrl+k+f to indent the code so it is far easier to see.
It is possible and most likely that other IDE's have similar functions available for developer that have this kind of minor annoyance.