Apps are not enough, however. First of all, some online services I use (like Gruvr or My511, nudge nudge) don’t yet offer iPhone apps. (This is especially annoying if they also don’t default to mobile-friendly site layout upon mobile access, grumble…)
But also, several very cool and useful online services are meant to play nice with the rest of the web.
For instance, I get value from my preferred social bookmarking service Delicious because I can use it to bookmark, tag, and comment on any page I happen to be browsing. And on Twitter I often tweet links to pages I find online. For these services, I want their functionality integrated with my iPhone’s Safari browser (since you can’t run two apps at once on the iPhone, and since the iPhone also doesn’t yet allow cut and past, grumble…)