Earlier quoted context omitted.
...except when I'm on desktop. GMail via web, every time.
That will change soon with Windows 10. If you're on Linux you have no choice. And if you personally had to maintain Gmail on the web, you couldn't do it yourself. Enormous time put into an application such as Gmail. So suggesting you'd build Gmail on the web vs an app is disingenuous to suggest. It's quite an edge case for many reasons.
I'm not suggesting I'd build GMail one way or another. I'm saying that since GMail web is available to me on my desktop, where I spend the majority of my day, that's how I prefer to use it. It's nice to also have an app, but that's way less percent of my time. And I think reading and typing in GMail is way nice on my desktop.
Sure, it's an edge case, but so is Reddit, so is HN, so is G+, so is Facebook, so is CNN, so is Github, so is StackOverflow, so is xkcd, so is news.google.com...
I spend way more time on those sites on my desktop than I ever would in their corresponding apps.
Add all those edge cases up, not to mention all the websites those things link to, and it's a HUGE part of my day. Apps? Sure. I like em.
And sure, when I'm on mobile, any given content is probably nicer in an app. But sharing, mixing, quickly browsing... web wins hand-down for me.
I wouldn't even know how to take a page from my CNN app (unless they give me a web URL) and discuss it on my Reddit app. Do you?