I write one of my characters in a 1st person POV and that is not even remotely why I do it. ESPECIALLY not the third point. xD
When I first started planning out my current novel, I wanted to have it written as a memoir by one of my characters. So naturally, the POV was 1st person. And as he is a thirty-something scientist, there's also little danger of me falling into YA tropes of oversimplifying the surroundings or diving TOO deep into his inner world.
The BEST thing about a 1st person POV? You can easily make your narrator unreliable, while also giving clues about what's the truth. That's something I'd like to expand on in the future (when I edit the novel....... AGAIN), but I would never write nor read a 1st person POV narrative that is used because the author wanted to put their own feelings into it. I'm sure that's great for a memoir about a real person (hence my initial plan to write my novel as a fake memoir—think Frankenstein, or The Remains of the Day), but other than that, I'm not a big fan of the POV and gravitate towards 3rd person.
And 3rd person offers intimacy just as well as 1st person, actually. It depends on whether you're writing with an omniscient POV or an intimate one that's close to the character, meaning that the reader still only sees and feels (or smells etc.) what the character perceives.
As I am a sucker for the intimate 3rd person POV, you're sure to find that in my current and pretty much any novel I'll be writing in the future lol; but I love playing around with 1st person—if it serves a purpose other than intimacy.