Buck, it's easier for me to bend the bamboo around a surface gradually like that instead of trying to push it into the curve of my form. If I were trying to push the whole bamboo into a form, it seems like that would create a lot of potential for hinges since it can't be clamped into place until the whole thing fits down into the curve. With the way I do it, I can add one clamp at a time, and heat a small part of the bamboo at a time. I have more control that way. I'm not sure how I would even do it the other way. I'd have to heat, then maybe tie a string around it or something to hold it, then heat some more, then tighten the string, etc.
And, consistent with what Pearl said, if I scorch the inside of the bamboo, it's not biggy. But if I scorch the node side, that could be a problem. I've seen people use a blow torch on the node side of the bamboo, though, to put scorched lines across it for decoration, and it didn't seem to cause a problem. But I haven't done it enough to know.