Correct.. Actually the existing POTS may be still 60% circuit switched, is already riding on layer2 data(as it is multiplexed-analog voice thru mic of telephone handset is converted to digital, compressed, transmitted to the switch, converted back to analog for the other-end telephone handset).

Difference would be, the voice will be considered as layer3 traffic(ip) packet-switched so you have MAC and IP to identify voice traffic. Parang viber or skype.

Wired data communication is STILL much reliable than wireless..