Not at all. I'm heavily involved in e-Commerce and the rule of thumb is: don't build an "app" for its own sake - websites are better.
I don't know what phone you've got, but the IE 9 on my WP7 device works fine. I doubt whatever Safari/Chrome equivalents are available on iPhone and Android are that much worse.
e-Commerce may be that way... but gaming companies hardly ever use web apps for mobile devices, from what Ive seen.
EA could have said: "Just use the Battlelog website on you mobile device." but instead they developed a better app.
343 Industries could have said: "Hey, Halo Waypoint is a website, just use that." but instead the developed an app for Waypoint instead. (And they're a Microsoft company that built an iOS app for crying out loud.)
Bungie could have said the same thing when they ran the Halo series... but they built an app to access all your stats and such.
And native applications will likely have a bigger set of APIs to pull from because they arent limited be being a web app.
Web apps are a cop out for companies that dont want to do the work to have to develop natively for Android, and iOS and WP7.
9 times out of 10 a proper native application will work better than a web app.
EDIT: Whats worse is the people said "We want an iOS app." or "We want an Android app." and Cryptic is saying: "Here have a junky web app."