Do you really prefer digging through years of commit messages to find why a particular line exists? It's a very impractical place for those. And good luck finding the origin of that line if there was an extensive refactor in between.
Also, how do you notify a later viewer that there's a "why" they should check? A comment that says "check commit messages for this line"? :)
Not to mention: you're losing the notes as soon as you move repositories, or worse, version control systems. Yes, I've hit the "SVN git migrate" wall way too many times. For that reason I even started leaving issue numbers in comments for when it's particularly important, in case we lose the commit<->ticket link down the line.
Also, how do you notify a later viewer that there's a "why" they should check? A comment that says "check commit messages for this line"? :)
Not to mention: you're losing the notes as soon as you move repositories, or worse, version control systems. Yes, I've hit the "SVN git migrate" wall way too many times. For that reason I even started leaving issue numbers in comments for when it's particularly important, in case we lose the commit<->ticket link down the line.