... plus may even bring unwanted ads to your phone?

I don't know - but that's how it seems to work. The whole iPhone industry is built on that. You may not know, but we even have applications in Extras-something (devil or test, don't know) that don't do anything but open the streaming URL of a web radio in the Media Player.

I don't know - I wouldn't want to use it, because I browse the web anyway. But a lot of people - especially those with devices that don't have good browsers, such as an old S60 with very small screen or an iPhone - will prefer to browse their "app-store" and discover an "app" that brings exactly the same content as other people see in the web browser. It's all a matter of preference and learned usage patterns, isn't it?