What type of player are you?
Well, honestly, I don't care. And you should not care either, because we play D&D to have fun, and people can have fun by both calculating every action to maximize the damage output or just throwing a bunch of dice at the source of problems.
Overall it is about all math-related stuff that happens in Dungeons and Dragons. It is mostly about combat and your efficiency as a character in combat. It also points at some major game balance issues, but this part will be done later.
If you're a DM and you have to considered throwing at players some evil genius or just very exeperienced combatant, consider that they would most probably act in the most efficient way possible. Also this will help you analyze the upcoming battle and make some important decisions.
If you're a player, you may want to optimize your perfomance in a combat-oriented campaign, or maybe just enable your niche build with some things that would highlight its strengths.
After all, it is just a small excursion into how the game works, so you may also read it out of pure interest.