hummm
just by looking at this I notice the following problems.

anyway I'm (unfortunatly) pretty sure a lot of auto traced vector will pop out
How much time does it take to fix those few errors as opposed to drawing the whole thing yourself?
To be honest, out of the things you circled only the ones in the nose and eyes would really be errors and the others would be up for de discussion. You can't be sure that they are wrong. You would just be guessing that it might have been different, but it might also be that the software was right.
Those few minor vectorizing errors are really only detectable by someone with a magnifying glass and the original bezel. Besides , I will say again, that I have several scans/pictures of the bezel and none of them are the same.
Another scenario is someone wanting to print that bitmap. Someone who has no desire/time/skills to vectorize the whole thing to minute detail, but who wants a bezel that looks good and fits in with the vectorized art that he already has.
The bitmap itself has a lot more and much more obvious flaws (the whole thing is noisy, has incorrect colors and it's fuzzy) So if someone is simply thinking of printing that bitmap, which would look better in print: that original bitmap, or the vectorized result?
This software can save a tremendous amount of time in vectorizing art. At the very least or it can help in scaling/printing bitmaps for people who don't feel the need for a pixel perfect copy of the art, but who do want it to look "tight".
:edit: also don't forget that the scan that you get is imperfect itself. I redid the Galaga sideart, because the version done before was vectorized just fine, but it was based on a very distorted picture.
The best (complete) scan of the Galaga bezel I have is the one from localarcade. This image has been digitally cleaned up though. This means that a lot of detail has already been lost (stars are gone, the blue nebula are eroded etc etc ). I have been trying to fix that from other pictures, but that takes a huge amount of time and it's keeping me from finishing the thing. So at a point you have to say it's as good as it gets.
It's never going to be perfect anyway and even perfect means something else to every person. Some people will clean up edges and improve on the original (which were done in haste, low budget and thus poorly). Other more purist vectorizers will vectorize to the pixel and copy that one example they got a scan off (which might have printing errors to begin with too) and introduce errors that in fact need to be corrected.