Many of the AP poll voters are beat writers for a particular team, who don't have much time to watch anything but the team they cover, either.
But regardless of the argument about watching games, coaches understand the games they watch. I have no doubt that the worst, dumbest coach in America understands the game better than, say, Mark Bradley.
The AP poll and coaches poll have almost always agreed on the #1 team, so the argument that there is any sort of large difference between them is weak.
In the few cases where they have differed on the national champ (ignoring probation-related differences), the coaches have always been right:
1997: Coaches pick strong Nebraska team over lame Michigan team with even lamer DB who stole the Heisman Trophy from Peyton Manning.
1991: Washington over Miami criminals (this one is really a toss-up and both polls were incredibly close.)
1990: GT over Colorado
1978: Southern Cal over Bama (USC beat Bama 24-14 at Legion Field and yet the AP poll voted Bama #1?)