It’s probably faster and easier to develop such applications for the Internet-connected smartphone devices, but you’ll certainly be limited in what you can do as most higher functions and capabilities probably won’t be available using this system.
One thing of concern to most developers is protecting their applications, as these web-based programs are usually simple text files that can be read by anyone with a text editor. As such, anyone could “steal” your coding and make their own application, distribute it for free, etc. This topic was brought up at a recent Palm webcast, and the Palm developer didn’t have an answer to this question. Time will tell on how developers can protect their property under this system.