Use a cheap Android device. If it has a front-facing video camera, then you can video chat as well. You don't need to put a SIM card in the device as you will be connecting over WiFi for home use. A cellphone is also more portable then a cordless/Skype phone - you can easily take your Skype calls with you wherever you go, as long as you have a data connection (WiFi or 3G). Charging is also easier, as long as you can find a USB port or USB charger, for which you should already be well covered. The cellphone will also double up as a spare in case your primary cell phone gives issues or is lost/stolen.
One advantage of the Skype cordless phone is that the battery life way better than that of a cellphone, but for obvious reasons. To counter that, you could buy a charging dock made specifically for the cellphone, and just place the phone back in the dock after each call, much like a regular cordless phone.
Another advantage of the cordless phone, is that you can often connect a Telkom line to it, and make calls through both Skype and Telkom, thereby replacing your existing Telkom phone.
So a few things to weigh up before deciding what to buy.