Smartphones are what I think of as "attention capturers" which are able to completely capture almost anyone's attention span for a significant amount of time. Other attention capturers include computers[0], video games, TV, books, chess. Each of these has varying capability as attention capturers but it is safe to say that smartphones are the strongest attention capturer for most people.

I believe that using any attention capturer for long periods is not healthy and should be avoided. The hard part for me is actually finding anything else to do in a new city without family/friends. Especially on a Tuesday night after work where it is less possible to go to a bar and talk to strangers.

[0] Smartphones can be included here.