Whenever I'm at a family picnic with people who haven't seen me for years, eventually everyone asks what I've been up to. No matter how I answer, inevitably one of my parents will say "Well he makes a D&D podcast", and no matter how the conversation goes, eventually one of them will ask "Well what's the point of that whole D&D thing anyway?
The first few times, I definitely stumbled on my answer, but after a while, I figured out it was easier to answer with my own question.
"Well, why do you watch your favorite TV show, or read your favorite book, or listen to your favorite music?"
Most of them haven't thought that hard about a lot of things, but to me it drives the point home https://speedtest.vet/ https://vidmate.bid/ .

The point of D&D is that its enjoyable. Unlike other games, you don't really definitively "win" the game, just like how you don't "win" by watching your favorite TV show or listening to music. It touches upon something very human in us. Like humans, each session is diverse, imaginative, full of possibility, and quite (literally) random. Each one is uniquely beautiful, with their own stories to share and memories to reminisce, even if some of them (like a lot of horror stories) have more painful lessons than others.
Anyways, that's my answer.

How would you answer this question? What's the point of this whole D&D thing anyways?

Fun

Interactive entertainment, with emphasis on 'interactive'.

The point is to meet with friends to have fun playing a cooperative game of improv play-pretend to solve tasks, riddles and conflict, influenced by the intelligent or creative solutions you come up with, and components decided by chance/dice, narrated by one of the players in the role of DM/GM.

Something like that.

My favorite way to describe it is an alternative to a typical poker night. But instead of cards, me and my best friends are hanging out, rolling dice and telling stories (that just have a flair of whatever campaign setting you are in)

The point of D&D is to roleplay 

The goal is to have fun.

The point varies depending on the person. It's like asking what's the point in a Nintendo Switch or a Kindle - it's different to different people. Some play it to roleplay, others play it to use battle strategies, others like the stories, some want the.creative outlet of making characters. All of that is right. It's just to have fun, and that looks differently for each person.

People act like this is the only game where the point isn't to win. Here are some others: "don't let the balloon hit the floor." "The floor is lava." "Punch buggy," aka "slug bug." "Catch." Snake, that old phone game. I don't think you can win that? Maybe you can.

Here's some that maybe push the definition a bit. Cards Against Humanity. Yes, it has points and you can win. But the goal isn't to win, it's to make people laugh. Players throw the game all the time, giving up points to make people laugh more. Super Mario Bros. People often call it "beating the game" when you finish the final level, but that implies that the game was playing against you. It wasn't. It was on your side the whole time. Did you win, or did you just finish it? You wouldn't say you "beat" Breaking Bad. And what of the games you play with no intention of ever finishing, hm?

Anyway. The point is whatever you want the point to be. If you're after an emotional catharsis where you can live out some kind of personal fantasy, then that can be the point. If you want to pit your intellect against that of the DM, that can be the point. Etc etc. For me it's too complicated to sum up cleanly.

It’s cooperative storytelling with an unknown ending, where differences in how the stories pan out are resolved by rules and dice rolls.  Furthermore, it encourages visual aids ala Maps and sometimes even other artwork.  The DM is the chief storyteller that has (hopefully) created a detailed canvas against which all the other stories are tied.  The point of D&D is the fun of shared creation.

Telling a story engages me on a creative level, telling it with the input and reactions of friends engages me on a social level, and the problem-solving, character mechanics, and battle tactics engage me on an intellectual level.

As someone who's pretty busy between work and family, I've had to evaluate my hobbies and focus my time mainly on the activities with the greatest return on investment. D&D is at the top of that list. When you have a good group, it's just a very rich experience that provides not only fun but can also foster personal growth in multiple areas.