The main thing is, an RX100M3 can zoom (optically) to any arbitrary angle within its range. The vast majority of phones cannot do that, all they can do is switch between cameras and zoom digitally (= cropping).
There are areas of photography where that is important, but I am not sure yours is one of them; for "selfies with your girlfriend or friends or family" you probably want a wide angle similar to the default one on most phone cameras anyway? If that is so, stick with your phone.