Whether we need apps instead of just a mobile browser is kind of a mixed question, really. A mobile browser that does everything that a normal browser can would eliminate the need for applications designed to run on just one site or for just a single purpose, which would certainly reduce the hassle involved in going and finding an application for every single task rather than to do something easily accomplishable on a desktop machine with a browser. The problem is really the screen size avaliable. Compared to the 1600x1000+ resolutions avaliable to desktops/laptops, mobile things are usually limited to about 6 or 7 inch screens and maybe 800x600 if you're lucky. Most webpages just won't look right at that resolution, and having to scroll to see anything but a header is far from ideal. Making a higher resolution panel in a much smaller size has problems too, as some people already complain about a 1920x1080 17' laptop having small text, imagine it on a 1680x1050 5 inch screen. We don't want to have to bother getting a different application for every minor task we want to do and every website we visit, but we don't have the visual space to have a fully functioning browser either.