I've just taken a look here:
https://story.lightninggadget.com/articles/tvfix/en/aw-bigblue-bm
. . . and oh no, not again!
This type of product keeps getting launched in the USA, where cable TV is the norm in many parts of the country, as a fantastic way of getting TV without paying for a cable service. All it actually is though is an amplified antenna that receives the US equivalent of Freeview.
Then, a short while later, the same product gets launched in the UK (where the majority of viewers already have access to Freeview anyway) as some sort of wonder product. It isn't. It's just an amplified set-top aerial and buying it is a total waste of time.
There have been loads of AB threads about similar products in the past. e.g. here
https://www.theanswerbank.co.uk/How-it-Works/Question1558529.html
Avoid!