I have A LOT of flash lights. Probably dozens of LED flashlights. Again, mostly for late night hiking, reptile searching type (nerd) activities. For me, it's just not something that I want to carry in my pocket every day. My pockets already feel overloaded with wallet on one side and phone on the other. Of course, I understand that others have different needs, dress differently, etc. I get it.
First, do you know Stan up in WS? If not PM me, I need to get you in touch with the guy, I think you'd get along great with the reptile stuff.
Secondly - Since starting to carry a dedicated light again I realized how many times I need it. It IS more difficult to use than the phone light, quicker to deploy and brighter, But also I seem to use it quite a bit under desks, behind cabinets etc quite regularly.
And, like others said, saving power on your power is a good choice too.
With the size of these lights, like the microstream above, it really doesnt add much weight or space to the pocket.
I HATE full pockets. I dont carry a lot of stuff because I dont want bulky pockets. But with this light I find that since its clipped to the pocket on the side that I can still dig into my pocket without it affecting me and its so small that I do not notice it is there when walking around etc.
At my work we have ID badges, I clip mine next to my light so that the badge itself covers the clip - no peering eyes to question if I have a knife or not. Mostl wear khaki pants, but somethings dress slacks, sometimes jeans. It feels good in all of them.