If you answer the call, your number is considered good by the scammers, even if you dont necessarily fall for the scam. They will try again because they know someone on the other side is a potential victim of fraud. The less you answer, the fewer robocalls you will receive.

What can a scammer do with a Google Voice number?

Google Voice allows you to make and receive calls and texts free of charge. A scammer who gets a hold of your number would need a verification code to activate the account. Once they have it, they can use Google Voice to cause all sorts of mischief using your phone number.