The Nats used four relievers today, so your point is invalid. Besides, you can certainly blow through a pen -- and blow a great season -- playing in that stupid one-game wild card playoff.
Using 4 guys in September isn't blowing through the pen, especially when Wang, Garcia and Duke are 3 of the 4 you used. And today wasn't a one game playoff, that really isn't in jeopardy. If we do get in that situation, then it's a different situation, but we're not there right now.