People are fukking stupid. They bet more in general on NFL than other games just because there are fewer games in a season, so in their stupid heads that means bet more. Then playoffs come and they start playing double, then Super Bowl comes and for some reason, that means make it your biggest bet of the year because it's such a 'special game'.
I always have a 1 unit equivalent on each game I play, whether it's the Leafs vs Senators in NHL or the Super Bowl.
Because some times teams are frauds and you know the playoffs will be their day of reckoning so you pound away. Much easier to predict than a random week 7 game. Totals might be a bit harder.
The biggest reason is b/c it's a bigger game, it's for sure gonna be on TV, the touts come out with their stone-cold-10,000 dime lock specials and people are degenyamines and plunk down megabucks.
For some folks, maybe they wager more b/c they have a full season of stats to look at; there's a ton of analysis being done to each game on TV and the internet and newspapers/magazines......
But mostly b/c people have always bet more on Championship games then regular season games and they're sheep and think that's just what you do.