What are the advantages of using an IPTV device such as Mag425A over IPTV smart software such as STB software?
We do not compare a device with a software in that case, because portal software can also be used on android MAG devices too.
You should compare a -smart TV- with an -old TV equipped with a BOX-. In that case, the main benefice of a BOX over buying a whole brand new TV is the cost.
You can keep you great old but looking new TV, and equip it with a BOX to use the full potential of a smart TV.
Is MAG a good idea for a new box?
Give a try to that mag420 https://www.infomir.eu/eng/products/iptv-stb/mag420/ It's a small set-top box, it's inexpensive. But with this console, your TV will have more features. A built-in Wi-Fi module, USB 3.0 and Bluetooth 4.1 support allow connecting any external drive for extra storage space or a keyboard and mouse for comfortably using the set-top box. The whole my family simply adores it!