What's the point of dic pics?

I'm a guy. I never actually understood the concept of some men sending dick pics to every other girl. I often wonder what goes though the minds of these people who decide to shoot dick pics to others...let me send a dick pic and she'll get seduced by the sheer grith and awesomeness of it? I mean apes think better than that. That's like the worst opening a person can make. I understand when you do some sexting and then you share your dick pic to turn the heat up but seriously what's up with this no hello/hi instead I'll send my postman to deliver 'a direct message'? Does that actually work? I mean why would someone keep shooting dick pics if that doesn't work? So if someone here can enlighten me why is this a thing, please do. Honestly curious.