As a member of an emergency service (CFS in SA) my only concern is people who rely on VOIP and live in area that does not have a reliable mobile service.
Remember that VOIP relies on the mains power, which can be cut during extreme weather (either as a result of the weather or by the supply authority as a precautionary measure). If your mobile doesn't work reliably this can leave you in a compromised position.
Of course, the same thing applies to those that have a wireless hands free telephone, if the power fails these devices won't work either.
So, we keep a landline but use VOIP for interstate and international calls...
HTH

