Let's not act like suddenly it is something so out of place in a spy thriller. It's obviously a genre nod. Like, so obvious.
They set up a few things before and use them again to surprise the audience, like the car floor cutting laser or BW's electronics disabling gadget, so I'm pretty sure they are aware of how things are supposed to be set up in a movie so it doesn't seem out of place, but setting the mask up would absolutely remove the surprise in that last scene. What is set up several times is that BW is a top spy, with all sorts of martial arts training and gadgets, and that they are on a very important mission infiltrating SHIELD HQ. They all have their role during the infiltration portion, and BW is nowhere to be found. It was so obvious she was doing something behind the scenes to help the team, and there it was.
The mask is a neat fan-service moment for fans of these types of moves, nothing more. A Deus Ex moment would be: "Oh, so now Widow knows how to infiltrate buildings" or "Oh, so now Widow knows how to fake accents" or "Oh, now Widow knows martial arts" or simply Widow appearing in the room out of nowhere, with no idea how she got there unnoticed... all of those things come together in that scene. All of those things are character traits that have been established for several movies now.
Chekov's gun is actually like the opposite thing too: for example, setting up they have that face technology early on in the movie, then never using it, thus no payoff. This wasn't that at all.
How is it that hard to accept that? Some of you guys will nitpick everything, even cool reveals or the directors acknowledging their inspirations.
