Like you all I rolled my eyes at this scene in the movie because it felt poorly executed, likewise my wife called it out afterwards saying it felt like unnatural pandering.
When discussing it with my family sometime later I was surprised to find out that it was my younger sister's favourite moment in the movie. She said it was nice to finally have a scene where the girls got to shine together as a team but in the process helping the boys. I don't look at the avengers as a boy team but for her that's what they were even though she likes the movies. She grew up with three older brothers and always tried to keep up with us rather than doing her own 'girly' thing, so black widow being the only girl on the avengers was probably quite close to home for her. She also played netball at a very competitive level and if it was a boys sport she would have been able to turn professional and earn a living from it but being a girls sport it naturally receives little to no attention or funding. So from her perspective I can see why it would mean something, the girls can be just as useful as the boys. Switching the focus to them, if only for a moment, in the final battle of the mainstream juggernaut that was the Infinity Saga was perhaps even more significant given that the main climatic narrative thread culminates in the three male leads, Thor, Cap and Tony going toe to toe with Thanos whilst black widow (the original female avenger) was long dead and forgotten by the movie at this point.
Sure it made me roll my eyes but it didn't bother me and if it gave her something and other girls like her then they were right to put it in the series.