About 2 years ago Canon released this software that would be compatible with a lot of their cameras to be used on a pc as a webcam, they've since added some PowerShot cameras and it got me thinking, Will Canon add compatibility to the PowerShot G16? It's the camera I have and it's not yet compatible with the software. I spent a lot of money on this camera multiple years ago and I don't really wanna have to buy a new camera just to be able to use it as a webcam for my streams. It would be really convenient if Canon themselves replied to this telling me if they will, if they won't and the reasons why.
Canon has an official list of cameras that are supported by the EOS Webcam Utility. There are only a handful of Powershot bodies listed, and all of those are recently released models. The same is pretty much true for DSLRs. Many older DSLRs are not listed as being supported.
In some cases, users have been able to get unlisted DSLRs to work. My 1D Mark IV is not listed but it works like a charm. It seems like if the camera body is able to be controlled in a remote shooting mode by a computer, AND it is able to record HD video, then it may work with the Webcam Utility.
I do not know if the above is true for the Powershot series. Both video capture and remote shooting control seem to be the minimum set of features you need. Still, having that capability in the camera is no guarantee that it will work. Remember, the camera may not be officially supported for use with the Webcam Utility.