I learned defensive pool playing from a group at the Cadillac Ranch in Southington, CT.  They were masters of defense.   Each shot has an offensive component (the object ball you're trying to sink) and a defense component (how and where the cue ball stops for the next shot).    Each shot is a compromise between two goals.   One shot may be 90% offense  / 10% defense.  The next might be 50% / 50%.   Determining the optimum ratio for each shot is the skill of the game.

An offense player wants only to sink the object ball, so he has a singular focus.  Given the same skill level,  the offense player will be more accurate than the defense player.   But accuracy is only part of the game.

A cowboy came into the Ranch, visiting from Texas.  He watched us play for awhile and decided he could make money on us, as our accuracy didn't meet his expectations.   We never played for money on weekends but someone finally gave in, matched his $5 and racked the balls.  Fifteen minutes later, the cowboy was out $5.    But.. he wanted to play again so another player matched his $5 and played.   Then he was down $10.   But the cowboy wouldn't quit...

After losing $15, he stepped back, pushed his cowboy hat back, scratched his head and said,  "Well, dang, there's something goin' on here Ah just don't understand". We burst into laughter and someone said,  "You don't understand defense".

The binary virus also has an offense and defense phase.   In a normal virus, the two phases are muddied together, just like our Texas cowboy's shots.  He's not making a conscious tradeoff of offense and defense so he's a less effective player .  In the binary virus, the first phase (mobility) is the focus for most of the virus lifetime, until the second phase (mortality) kicks in.

Understanding of two distinct phases creates effectiveness.  This is true of sports, games like chess, Risk, divorce court, war.  There are offensive measures, defensive measures and the correct time or proportion for each.