There's been a trend of "full games" not being printed on disc these days when they're printed on disc (see for example DOOM The Dark Ages or even Halo I think?). Ie. mandatory day 1 patches that are required to play the game in the first place which without an internet connection you won't be able to access. It used to be that you'd have a full gold master on the disc and could play fully install the game offline and play it with no issues. However, that requires additional time and resources poured into it - it's easier to release an unfinished product and add to it after release than have it fully finished in the first place.

I can't find a pic of the label on the box that says "Internet required", but it's been used more often these days: