@goatsarah I cannot count how many conversations I have had with my elderly mother about this one. Yes, VOIP behaves just like a regular land line (and indeed I've had one for a while now). No, just because it's connected to the Internet, that doesn't mean you can look at websites on it. No, you do not have to worry about anything. Rinse and repeat.
She's basically got all her marbles, but she's 85 and her memory is tanked.