Why would I use an app for something when a web browser provides a better experience with fewer bugs and a richer feature set?
The app and mobile site quickly run out of memory after a page or two of gifs.
The app does not allow you to open content in other tabs. This is problematic if I want to follow a trail of links and resume where I left off in the feed or comments; I have to mash the back button repeatedly. Additionally, I can't open a new tab to look into comments or a link later.
The mobile site and app have issues with sorting by top / newest every now and then, and often will fail to load content altogether - leaving the user with a white screen. (I've reproduced this in firefox & chrome on Android, and safari and firefox on iOS)
The mobile site and app take longer to load comments and additional content - and sometimes fail to load all together. Whereas the desktop version of the site loads almost instantaneously and almost never fails.
The app does funky things with copy pasting of text.
The mobile site sometimes crops half the images, making it a pain to click through.
Downloading images / saving getting an images source URL can be a pain on the mobile site / app.
And of course, the mobile site spams you constantly to download their app.
I can't use an adblocker, privacy related plugins or browse incognito in the app.