@Gusse,

That's a really good question/observation

I've only started using swap on SD (only, no striping) a few days ago. Cannot really tell if performance is better (perhaps a bit, but I may have been subjectively biased..).

So far I have not noticed any difference in battery life/consumption, but it's been only three days..

I'll try to keep an eye on this and maybe do a test or two..