"'questionable decision': that depends entirely on what the Mac, Linux or Windows user wants to do, surely?"
Well, that's what one would question, isn't it? Probably something along the lines of "Are you sure you don't want to...", followed by a very long list of commonly used features of the other platforms that aren't available on RISC OS.
In your case, the important items on the list would be "use it on the move" and "access Flash-intensive websites", presumably.
Don't get me wrong, I still use my RPC for e-mail, usenet, and a few other things, but that's mostly because I always have. I also use it for browsing a small set of websites, but mostly I use something on the PC for that, nowadays, so I can watch video clips, etc.