I agree that the BH sounds like considerably more than a CGC, but a CGC is considerably more than "breathing and hasn't bitten anyone". (and the 2nd part isn't necessarily true. A dog could bite someone, and still get a CGC, they just can't have bitten someone during the CGC.)
A BH is considerably more than a CGC. It is also considered a basic temp and OB test that one must pass in order to go for titles. Judges do have a fair amount of leeway when judging these. Some dogs can fail a few exercises, but if they judge thinks the dog has what it takes to move on, they'll over looks somethings like dogs coming to heel instead of a front, or downing on a sit in motion or vice versa. Where in a trial for a title you'd be penalized much more heavily and probably won't pass.
Here's a video of a nice BH done by a friend of mine to give you an idea of what the OB portion is like.
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