I prefer a zipped pocket for my phone. I do have a pair of trousers with a phone pocet on the right hip, high up, which is a great place for one. It's not zipped, but is pretty secure.
When I'm using my phone eg as a shopping list in the supermarket, it has a little leash from the case to one of my fingers. This is useful also taking photos or using a gps app. I have two cases, each fitted with a leash/lanyard via camera hole.
When I'm at home my phone is always in a little desk organiser next to my bed.