It's not just a public place, but a very specific type of public place: a shopping mall. Were it just a public square with people from your social circle, then it wouldn't be as dangerous.
As a shopping mall, it's full of advertisements, slot machines, games, fast food, sales clerks trying to lead you into the place they want you to be, etc. But it is also the place where almost all your friends are, and almost all the books and newspapers are.
It's hard to leave it because it has valuable things inside (even your office might be inside the mall), but it's also hard to stay in without having your agency taken away by everyone competing for your attention. You could get a book from the bookstore, read it and talk to your friends about it, but it's hard to do that in a mall where everything is designed to take you to their stores, entertainment centers, etc.
Not to mention that slot machines are notoriously addictive and most apps that aren't games have been incentivized both by advertisers or in lieu of additional advertiser revenue to include variations of slot machines in their feature lists because that attracts attention and keeps attention.
As a shopping mall, it's full of advertisements, slot machines, games, fast food, sales clerks trying to lead you into the place they want you to be, etc. But it is also the place where almost all your friends are, and almost all the books and newspapers are.
It's hard to leave it because it has valuable things inside (even your office might be inside the mall), but it's also hard to stay in without having your agency taken away by everyone competing for your attention. You could get a book from the bookstore, read it and talk to your friends about it, but it's hard to do that in a mall where everything is designed to take you to their stores, entertainment centers, etc.