There's a good reason for dubbing this "hardcore mode".
First person in PUBG is a little more daunting than third person as the view point constrains what you can see, naturally. The third-person view allows players to have a better look of their surroundings and check around corners for possible danger, while the first-person view is often used for engaging against enemies for better accuracy.
If you want more realism from your game about 100 people hitting each other with frying pans until one wins a chicken, first-person-only servers might be for you. He said the update will be rolled out first to North America and Europe solo and duo games, but would eventually make its way to the rest of the world after more "polish". According to developer Brendan Greene, a dedicated first-person mode is coming in the game's upcoming monthly update.
They are set to be added to the game in the next update, and will not be replacing old servers but adding new ones.
Lead community manager Sammie Kang, also known - apparently willingly - as "poopieQueen", confirms that the first-person mode will have an FOV slider.