You are certainly correct that comparing the functionality of this (or nearly any) DYI-ish stove to the Bushbuddy is like comparing... oh, I don't know, I can't think of a real good comparison.
However, saying that it's not worth it to bring a stove as compared to gathering rocks is not correct.
1) Stove are far more stable and less likely to spill your dinner.
2) Stoves are a bit more efficient and far less finicky to keep a relatively small fire going (aka a twig fire), due to a number of factors.
3) Stove have the potential to result in less earth scarring (Actually, a rather simple modification to this stove would wind up in zero earth scarring).
So, if wood is going to be a last-resort backup, yeah go with gathering rocks. If you're likely to use wood on a regular basis, a 6 oz stove is a pretty cheap (weight wise) investment.
EDIT - HUH! For some reason, when I started posting, I didn't see JK's comments.