For me, an LC9 sized gun won't fit in the pockets of the pants I own. I know because my shootin' buddy has an LC9. I do have a Glock 36 that is a bit larger than the LC9 and it won't fit in my pockets either.
The 36 is saved for the few cold weeks we have when I'm not working, which allows me to wear a jacket and a shoulder holster. But that is rare.
Why do I choose to pocket carry? I'm essentially a mechanic of sorts that has to wear a tucked in shirt but no jacket. That alone isn't the problem, as I have to work on my knees, on my back, on my sides, and of course on my feet. My first carry gun and holster is/was a Taurus 85UL carried IWB. I found I could get by carrying that revolver in my pocket more successfully at work than carry it IWB.
Having a gun in a pocket puts that gun on my upper thigh. I can work for hours in weird positions with a small gun on my upper thigh, but I can't do that with a lump of gun anywhere on my waist. Same goes for working on things at my house. In the attic for the AC or underneath cars in the driveway.
Sure, drawing from the pocket in any of those positions is problematic. But I'm hoping that when I'm working on a customer's machine that I don't have to keep watching my back. Having a gun in my pocket is for the times in between working on machines whether for work or at home. Being able to upsize the gun and change to an IWB/OWB holster isn't something I can do readily unless I'm at home.
Of course, that's just me. Others have their own reasons.