That is especially fever for desktop computer users or at any *urgent time(emergency), *hardware failures regardless desktop computer or laptop etc.
While client application allows to make or answer both video and voice calls as mentioned above then the notification able to set for display as optional similar below
_"Wire doesn't have access to your camera/microphone. End user(users) will not be able to see you or hear your voice. 'read support article' to find out how to fix it._


Fast fix for this is to use virtual webcam driver, like this one: http://classic.makesweet.com/webcam/ucanvcam/
@survivor303
Yes but cannot play with public or enterprise devices as our personal computer. by the way if we use wire for official task to communicate with clients, it seems that is very uncomfortable.
Fast fix for this is to use virtual webcam driver, like this one: http://classic.makesweet.com/webcam/ucanvcam/
Useless
Closing this as the user is already able to answer calls with no microphones or blocked microphone access.