> provide the best user experience was through a mobile app

Having to install an app is always a bad user experience. It's a dealbreaker for me for just about every case, and in general it's got to add a lot of friction when you're trying to get people to sign up.

It would be interesting to hear some honest discussion of the tradeoffs. I assume most companies prefer me using an app because it lets them run arbitrary code on my phone, access contacts and whatnot, and send me notifications. Is it also materially easier to write the code for apps? Is that a legit reason why companies prefer it? And is whatever companies are getting out of forcing their users onto an app worth the potential users they lose because of it?

I often hear this rationale when starting with a social app, but I think that you may find that you pigeon hole your age demographic by only doing an app. Folks that are in the prime professional age bracket (gut check, late 20's to 30's) are going to spend more time on a larger screen device than they are on a smaller screen device. At the very least, if you're not planning on developing a tablet app right away, having a browser option is at least a stopgap between running a phone-size app on a tablet, or not at all while you work on that.

No idea if you're building your app in a web framework that ports to mobile easily, or what your choices are around that, but I'd highly recommend reconsidering not having a web app if it's at all reasonable for your time table.

For me? I hate typing on my phone, so I probably would pass on this until a web app is supported.

What exactly does a mobile app do that a web page can't?

Web pages play video and have interactive components just fine.