Well, I think it's primarily about piracy.
And while games will always be cracked it's still the age old game of raising the bar to make it more difficult for hackers to crack the game (or at least slow them down long enough to increase the window for sales).
Interweaving the game with the internet is just a logical step. I think it's safe to say that an offline game is easier hacked than an online game, and the more points a game uses to connect with Mama the more difficult it becomes.
I assume next (if it's not already done) will be to only deliver parts of the game initially and download important data later, which can be additionally secured with version checks and hash files of essential files. Perhaps the mission files for SH5 are already handled such a way.
And one step further would be that a game will never be again released complete, but parts of the game engine will run on a company server.
Don't get me wrong, I'm not condoning this, merely pointing out a potential route this could take.
And actually it's not that much of a problem. The major factor (besides the general paranoia) IMO is convenience. As long as security measures and DRM doesn't interact or obstruct with the act of gaming it doesn't really matter. I disliked GWFL for playing Bioshock 2, but 98% of the time I didn't notice it was running and it never obstructed the game for me.
What's most bothersome in the case of the new UBI games is indeed the (potential) inconvenience. The main reason is indeed that the DRM works as a shell around the game instead of being a part of it. That's the problem of publishers coming up with their own solutions without communicating with the developers. Otherwise you could easily implement a system to deal with an interrupted connection without causing too much inconvenience (if only "Your internet connection has been lost. The game will create a recovery save and you will be able to continue once the connection is available again").
@Zarf: I know that ads in games is a hot topic for publishers, but of course that applies only for a percentage of games (unless they really start integrating ads in the old fashioned way: Ad Breaks

). And I'm not so sure about player patterns. If anything in connection to ingame-ads to verify that those ads are spotted by the game. Anything else would either be interest in behavioral science (d'oh) or gaming feedback, not the most probable motivation for a publisher (contrary to a developer).
Second hand? Are these measures actually messing with second hand deals? Are the games tied to a specific account by serial numbers?