Auto-block is something only inexperienced (or people who never really learned the melee mechanics) players truly benefit from. The fact is, most cRPG players are good enough that failed blocks aren't the primary reason people lose. It's footwork, timing, and mind games.
I've experimented with macros, and find them to be sub-par compared to regular intuition. You essentially limit yourself by over committing- and forcing the other player to over commit is the primary mode of defensive exploitation that a skilled melee cRPG player uses.
All this works against the average player of 2013 or some new-ish player now. I'm not sure what advantage it confers to anyone today aside from sheer laziness in grinding or some shit, even if it's used. I'm not even convinced it is regularly used.
tl;dr Auto-blocks and macros are tools that only benefit newbies/less curious learners. Since there aren't many newbies around, it doesn't make sense for many cRPG players to utilize it.
Edit: what is shown in that video is also possible by simply holding down attack at all times, as well as certain settings (high sensitivity, artificial acceleration, and deceleration) that are not useful (they hurt you, in fact) for fps and mobas.