My wife almost fell for this Facebook Zelle scam — watch out

I do not understand how giving someone your phone number puts you at risk. It's easy enough to look up anyone's number anyways. What can they do with your phone number? Or is this just a sign of a scam in he making?

Thanks!
 
I do not understand how giving someone your phone number puts you at risk. It's easy enough to look up anyone's number anyways. What can they do with your phone number? Or is this just a sign of a scam in he making?

Thanks!
It links a phone number to a facebook group centered around selling things (money involved), and to a human who is potentially gullible enough to give a working personal phone number in response to a scam email.