Yes, to quote a multi-platform developer:
"Writing code optimized for the PS3 and using threading policies that are suited the SPUs is a given, because not doing so would not be acceptable at all. All our multithreading is done on PS3 first without exception, and other platforms emulate SPURS."
"Secondly, the matters of multithreading policies, the whole job queue architecture, encapsulation of jobs and their corresponding data packets, etc. that work on the PS3 are indeed more than applicable of the 360/PC. And as I've mentioned before, they work better than anything and everything that Microsoft recommends (so far without exception for us). The problems lie in the fact that that work is an absolute necessity on the PS3, whereas they're not entirely necessary on any other platform."
That's pretty much at the core of the issue. Writing PS3 friendly code, will also result in better performing code on other CPUs. Of course the Cell is by far the most powerful console CPU, so the gains here can be much bigger potentially, but that won't be the case for most multi-platform games as for example you can't have one version of the game have twice as many onscreen enemies than another version without considerable redesign.