When you first experience a real problem virus or otherwise you will sing from a different hymn sheet. I have never used my drive image software to restore after a virus attack I haven't had one since using avast (over eleven years).
But I have used it for other computer relates issues, for me if the problem is going to take more than 30 minutes I go back to the last weekly image backup. It has saved me a lot of grief over the years.
You won't believe the hassle if you ever have to restore back to a certain date - just setting browsers, email programs, customisations, ad-ons, etc. etc.. A bad windows update comes to mind.
Its your system and your choice, but what I can't fathom is why all of these questions you have been asking and then trusting to luck if you ever get hit.