It’s really just a fun app from Google, which, in my opinion, isn’t so much to be hyped about. The craze would just be like that of Prisma’s, a picture editing app that went viral last year, but eventually faded in the crowd of such applications.
Indeed Google Arts and Culture app has a USP, unlike others. The basic concept is interesting. It helps you compare your selfie with paintings from centuries’ past, helping you find your doppelganger in fine art history. So have you been wondering if you look like Mona Lisa or other historic figures, this app is a great choice to home in your phone.
However, for now, the official app is only available to people in USA. You can still use it through backend channels.
At the end of day, it’s another interesting app from Google. Sadly, people will eventually get bored of it after using it for a week or two. Because it isn’t a traditional image editing app! It’s a one-of-a-kind concept that people will stop liking over the course.
And also, to your question, it fills no purpose. It’s a fun app!