One thing to be wary of as with most voip providers is E911. I'm not sure if Plivo offers it but it's worth looking into before venturing down this path.

From their terms of service it doesn't appear that they do offer it.

"You also acknowledge and understand that Plivo does not currently allow you to access any 911 or similar emergency services (no traditional 911, E911, or similar access to emergency services). The Services are not intended to replace any primary phone service, such as a traditional landline or mobile phone, that may be used to contact emergency services."