Sirlin makes this point himself in his book:

http://www.sirlin.net/ptw-book/love-of-the-game-not-playing-to-win.html

Now it’s time for what appears to be the opposite point of view: “playing to win” at all times is counter-productive. If you want to win over the long term, then you can’t play every single game as if it were a tournament finals. If you did, you wouldn’t have time for basic R&D, you’d never learn the quirky nuances that show up unexpectedly at tournaments, and you are likely to get stuck honing suboptimal tactics.