That article seems to be full of inaccuracies.
The Current Now TV box is a re-working of the current Roku 3 with a custom Sky firmware, with a restricted channel store - no access to anything like Amazon, or netflix or anything else that is in competition with Sky it does however have the main UK catch up services such as BBC Iplayer, Itv player, $ on demand, and demand 5, its main purpose is to push Sky content. A full Roku 3 costs around £99 a Now TV box costs ( roughly ) £25
This new Now TV box looks like a Roku4, however that article mentions a hybrid cable box, From other sources this would most probably be closer to a Roku box with an antenna input which can receive Free to air broadcasts from an antenna, unless their is some on board storage having an incoming antenna feed wouldnt be worth the effort.
Having a Guess this is what it could be:
A Crippled Roku box running Skys custom firmware, with no access to competing products (amazon/netflix etc)
4K HD on selected premium pay Sky more money channels
Live Recording/time shifting of Terrestrial UK Digital free to view TV (Freeview)
Possibly offering the ability to record programs via an app/remotely from anywhere with an internet connection
Possibly even offering the ability to stream content from the box, either recorded material, live TV, or something from an on-line stream to a remote device connected to the internet ( similar to a Sling TV box )
Cable Tv in the UK is restricted to mostly urban areas, and its not everywhere, if you have it you have to have a Cable TV box supplied by the cable TV company.
Sky also operate a DSL service/VDSl service to most parts of the UK, however unlike other ISPS you have to use their router/modem, if you want a better modem/router your out of luck - its either Skys own DSL/VDSL modem, or a two box solution
Likewise for Sky Tv ( satelite) you must have a Sky TV supplied box
You can buy other satelite set top boxes ( such as freesat) , however you wont be able to subscribe to Sky Tv with them.
Freeview is the name of what replaced free to air analogue TV and there are a multitude of Set top boxes ( digiboxes) Converter boxes, and of course TVs with it built in, plug in an antenna and your good to go.
If you use any equipment that is capable of receiving live broadcasts you are required by law to have a Tv licence, usually one per premises/house etc which covers multiple devices https://www.gov.uk/tv-licence
this funds the BBC and you have to have one even if you dont watch any BBC channels, even if you subscribe to Sky (satellite) or Cable you need a TV licence as well on top.