Who care about the coupon??? I am looking for as much privacy I can get baring spending the extra bucks for a roomette. BC is about the only way to do that. And a burger in the cafe costs $7..95. The $6.00 covers at least part of that. A lot of people make fun of those burgers but I find them pretty darn tasty.
Between the water bottle and coupon, you've maybe got a total of $7 worth of goodies. And the only other benefit of BC would be that it might be quieter, if most people don't choose it. So if you're spending $50 extra, then maybe you have spent about $43 net to upgrade, hoping that most people choose coach. I don't see how that's worth it.