"For me, it's the difference between being able to have a life and not. If someone takes a photograph of me and posts it, within two seconds they've created a marker of exactly where I am within 10 metres," she told the publication.
"They can see what I'm wearing and who I'm with. I just can't give that tracking data." The 26-year-old is instead offering some proper facetime.
"I'll say, 'I will sit here and answer every single Harry Potter fandom question you have, but I just can't do a picture,'" she said.
But there are some exceptions.
"I have to carefully pick and choose my moment to interact ... When am I a celebrity sighting versus when am I going to make someone's freakin' week? Children I don't say no to, for example."
It's that mentality which also helps shed light on why Watson remains intensely private about her boyfriend, William 'Mack' Knight.
The actress admitted that it's also because she doesn't want to be viewed as a hypocrite.
"I want to be consistent: I can't talk about my boyfriend in an interview and then expect people not to take paparazzi pictures of me walking around outside my home. You can't have it both ways," she said.
"I've noticed, in Hollywood, who you're dating gets tied up into your film promotion and becomes part of the performance and the circus. I would hate anyone that I were with to feel like they were in any way part of a show or an act."
While fame certainly doesn't come easily for the Harry Potter star, she also knows when to take a break from it all.
"There have been hard moments in my career when I've had an agent or a movie producer say, 'You are making a big mistake,'" Watson said.
"But what's the point of achieving great success if you feel like you're losing your freakin' mind? I've had to say, 'Guys, I need to go back to school,' or 'I just need to go home and hang out with my cats.' People have looked at me and been like, 'Is she insane?' But, actually, it's the opposite of insane."
