Writing in HTML/CSS gets you some of the benefits of the Web, eg cross-platform, portability, backwards compatibility, an active base on which to develop (new w

Writing in HTML/CSS gets you some of the benefits of the Web, eg cross-platform, portability, backwards compatibility, an active base on which to develop (new web standards are being developed all the time). It's also familiar to a larger pool of developers, which I agree isn't the greatest argument if your goal is quality. Don't underestimate the power of working on top of a platform that is being actively worked on and improved by a large pool of developers. Even if the platform has large deficiencies compared to some other platform, the rate of progress is going to make the Web win eventually, as long as you don't look at very specific metrics that happen to be Web pain points. (cf "Always bet on JavaScript") As for fitting in with an OS's look and feel, that is indeed a current weakness of HTML/CSS, but there is energy behind fixing that (eg with Mozilla's desire to move away from XUL). So it's one of those things that will happen slower than you want in the near term, but faster than you expect in the long term.