The person that is using his 580EX II for a strobist setup more than likely did not purchase the flash for that specific reason. If they did then it was foolish overspending. They either got it for on (or off) camera E-TTL or as part of a larger wireless E-TTL system.
I use my 5 580EX for strobist work and I don't consider myself foolish... Ok Ok I use ETTL for wedding work but I still like the ease of use of the wonderful 580EX's...

Using manual flash indoors the wireless feature of Canon's 580EX line makes for fast setups...
Canon 540EZ
A quick addition of a 1/8" port and I'm all set. Heck, I can even throw one on my camera and use the AF assist lamp if I need to, or use them on my old film Rebel.

