>>212269042
Yes, it's there to show Natasha's skills in manipulation, including using her physical beauty as a tool. The viewer is made to think the bad guys have the upper hand but then comes the call from SHIELD to show that the good guys were in control the whole time and then Natasha strikes (like a black widow spider).
It's also just because she's sexy. Like the reveal of Steve and his new body in Captain America, showing it off for all the women watching.