With the manual modes coming into Android and IOS recently, the weird "processing" delay will be gone and there isn't really anything to justify showing off your Leica in public.
The lenses your phone has, made by the lowest bidder, will not match a good zeiss lens, or even soviet lenses. You'll also be stuck with whatever the phone maker has decided is a good enough aperture because there's not an easy way to change the aperture size on a device that small. So the depth of field will always be exactly the same. No tiny apertures leading to crisp fields where everyone's in focus, no wide open images where the one, and only one, object you want to study is in focus. So yes, there are quite a few justifications for a discrete camera even after phones fix their processing delays. A smartphone will displace the snapshot camera used 10 years ago, but it's not going to be physically possible to replace the versatility of a changeable lens camera.
I'd go further and say, mechanical knobs dials and switches can be operated without looking at them. with touch devices, i have to look at them, both to find what i want to do, and verify what i wanted to happen, happened.
Fundamentally, they're not obsolete. These are features that can't be duplicated without some clever additional device.
Welcome to HN, where I have heard sincere claims that someone who pulled out a "Thinkpad Thinkpad from 10 years ago in a full Starbucks if you like, but most people wouldn't enjoy doing it - and even apologize for it, if they got curious stares."