Fortnite is a classic battle royale game with an added twist of building mechanism.
That alone makes it more fun. Here are few other reasons.
It's free to play on all platforms.It's easy to catch up on but hard to master.It's action packed and has a fast gameplay.It's following the latest trend of Battle Royale games.It is forever evolving.If you regularly play they give 200 v-bucks to free battle pass owners every season. With 950 v-bucks you can buy the premium battle pass. Then with progression in premium battle pass you'll have an easy chance to grab 1500 v-bucks each season.There's a cohesive storyline going on that keeps the players interested.There are real-time/live events that are so much fun and have crazy enthusiasm about them. The events are usually hyped with smaller events and easter eggs and hints so it makes for an amazing experience.It's a game of Battle Royale for the mainstream gamers but also an Alternate Reality Game (ARG) for the unconventional gamers.The game has one time/real time events that are mind blowing and only happen at a set time.Several cosmetics are available that are fun and are in line with the current trend. They rotate every day and new ones are introduced frequently.It is the most widely available battle royale game that allows cross platform gameplay.The gameplay is remarkably well balanced.There is no skill based matchmaking so you'll never know if the opponent you ran into is a pro or a noob.The game keeps in mind that all sorts of users will be using it. To say it is censored. For instance, earlier eliminations used to be called kills but it was soon rectified when the developers realised that it need to be more friendly. This is just one example there are many more.The game keeps in touch with real life and makes changes accordingly. Say, Christmas is around the corner so the whole map will be more festive, there will be Christmas trees, Christmas cosmetics, Christmas battle bus and similar stuff.Regular updates are rolled out weekly to update the game data and to resolve the issues that arise.If need arises, instant updates are rolled out for certain issues.It is regularly improving and getting fine tuned as per feedback.The developers actually take into account the community feedback and takes timely action.There are always new modes available like Sniper Shootouts, High Explosives, Close Encounters, Wild West, 50v50, Food Fight, Slide, etc.
So, these and many more such factors that cater to every gamer ever are the reason why it's so popular and kinda better.