Tough question JC , i'd call it a toss-up.
I think it really comes down to the individual person and more importantly how a person handicapps.
If you're one of these sabermetrics math and stat guys , you don't have to watch a single play from a single game to crunch your numbers , but if the human equation is part of your capping you can probably learn things from watching and listening.
My problem is that i dont stress from losing (im so accustomed to it i expect it lol) but i get stressed from listening to these gosh danged blow hard announcers. You'll hear more shit from these commentators than you would from a marching band with diarreah. ... I usually watch with the volume muted and music playing in the background. (unless its a Bama game , than i listen to the bs)
...I do like what nfltrends said about rewind , thats the ticket for breaking games down afterward.