The primary function would be to use their webcam camera solely, so that it provide the best possible live stream video from your "CMOS
" sensor camera device!
Since a lot of webcam manufacturers include and incorporate built-in mic with their webcam. That's the main drawback with that, many users will not see, or understand how doing so will limited their system resources because of the extra work load it will put on their CPU processor due to further processing requirements the webcam mic put onto the CPU.
Here is thought, if your speakers are connected and plugged-in directly into your sound card output socket (how else would you hear the audio sound). The sound card hardware itself is a very FAST
processor component device.
Then their should also be a mic socket too, use it for that purpose that it was designed for. In some cases there could also be aux or line-in sockets too these have a slightly different use and function