Offline launching with Steam has always been hit or miss. There's been a common bug with Steam (don't know if it's ever been fixed), that if your forcibly close Steam before logging out because it was glitching or whatever, you can't run it again unless you reconnect. I can say from experience there have been times when I was in offline mode and for reasons unknown to me, Steam suddenly decided it needed to connect online and bam, I couldn't access any of my games.Can't connect to Internet is irrelevant since Offline launching has been a Steam feature for eons. Steam account hacked, okay, valid even if extreme/fringe scenario.
Just playing devil's advocate here because it seems there really is only a psychological difference that anyone can seem to offer - I fail to see any meaningful day to day benefit of running a game launcher-free versus through Steam. In both cases the game launches whether you're online or offline, game runs the same either way.
Or hey, say you have a game where an update breaks things? (This has happened A LOT with the Source SDK). If you have a DRM-free copy, you can download it, back it up, if things ever change in the future, you're still covered.
Also if you want a more probable scenario than a Steam account being hacked, the 2 step authentication has screwed me on more than one occasion. I've had times where my IP or hardware has changed, and it's asked me to post a code it's sent to my email address... except I never got the email. Not in spam, nothing. I request again, nothing. It eventually resolved itself a couple days later, but during that time, I couldn't play any of my Steam games.
I think some people have to have been burned to truly appreciate what a big deal DRM can be. Steam handles it better than most, but it still has shortcomings. The game industry as a whole does not give a DAMN about you being able to play your game. There are so many games now that require company servers in order to play, then they shut down said server after a few years, and you can never play your game again. With this happening more and more, it's nice to be able to have the game files, you know they'll run, and some company server and authentication (which may or may not be up) doesn't stand in the way between you playing your game or not.