Sparring with MMA/no gloves is very different from boxing.
Of course, situations do arise where your shoulder can protect your chin a bit. And it helps a lot - potentially.
It's just that situations as these do tend to arise far, far less often.
Generally, you don't really want to stand "in the pocket" in MMA.
When sometimes pro MMA fighters do this, it's more because they have often [too much?] boxing style sparring.
In MMA everyone from middleweight upwards (pros: from welterweight upward) kinda has a heavyweight's punch.
You can hit "harder" and naturally more to a point.
Granted, on the other side there's less mass involved and hard grazing punches aren't so bad.
I guess the point is:
Whereas on boxing you can stay cool in many middle distance situations from the defense and then fight or even counter back, it's a lot harder in true MMA because not only of the glove size but also because the opponent has so many options.
I say true MMA, because it's an ideal.
In the ring, even among pros, it is still 80% wrestler and occasional right swing-puncher vs 100% judoka, for instance.
(In amateur MMA, it's mostly pairings like 50% hooligan style boxer,50%BJJ fighter vs 50% Kickboxer, 50% amateur wrestler. Most of the time they fight completely in one mode)
The irony is that old school, one-dimensional disciplines like boxing still do prepare you very well to a point (you learn to strike and take a punch better then with most other methods) and have very favourable training modalities, so they're very much in use.
So many times, all the angles, setups, counters work well if your opponent uses "moments of pure boxing" as his main standup tool. Which they do a lot.
But try that against a guy like Machida.
If you now say: "Laughable- Machida is a UFC pro, and uses a totally unorthodox style."
I say onto you - Guess what, that's what ALL nonboxers do.
They might not be so refined with quirky Karate tricks, trips, setups and distance.
But most guys here will know how strange it is sometimes to fight against a talented guy, own weight class and above, who uses his body mechanics well but isn't technically refined yet - but is basically a beginner.
These can be tougher nuts to crack then far more experiences technical fighters, BECAUSE he doesn't react conventially.
Note: nearly all great champions [Emelianenko, Spider Silva, GSP, Shogun Rua etc] transcended their methods, being able to fuse at least two schools together at one moment.
That's why their opponents often look like complete amateurs.
Look how silly Okami just looked. Silva felt exactly when his opponent would use his moments of "pure boxing" with his own style, with mostly 1s and 1/2s.
He took nearly the whole first round to get the timing right, then unleashed.
In boxing, this would have been an ok approach for Okami, even though Silva is a better boxer then Okami.
Silva wouldn't have been able to build upon his temporary dominance and finish him. (Which is btw the most important aspect of MMA, in my opinion at least)
He'd also slow down quite a bit through 12 rounds.
Okami could have gone full defense in the 2nd and tough it out.
Who knows, perhaps in such a boxing match Okami would dominate Anderson in the later rounds. I'd say he chances of victory would be maybe 20-40%?
Before japanese referees, he might have even taken the first as we saw it - he hit with some of his jabs.
Arg, I'm typing too much and now I'm out of time. I wanted to resurrect my punching thread, well maybe tonight.