It’s Easy to Break
Putting stuff in your pants is a great way to protect it. If you have a cellphone in your pocket, you know it’s safe. No one is going to steal it (but if they did it’s a fun way to get to know someone) and it’s not going to get broken because you tripped and dropped it while watching a YouTube video of a kitten sneezing. Put that exact same thing on your wrist and it’s broken within a day. That thing is going to get smashed the moment you throw your hands up in the air like you just don’t care and accidentally smack someone in the face.