Rob, I think you're seeing a placebo effect. Do you have any metrics to actually show the performance improvement, or did your phone just need a reboot?
I ask this, because in my work in the defragmenter business (we wrote the engines for the one you're using, BTW), the idea of defragging solid state drives was researched very thoroughly. Yes, they can be defragged, but there's little to no improvement in performance, and over time, you can actually do more harm than good. Here's an article that describes things pretty well:
http://ask-leo.com/should_i_defragment_my_usb_flash_drive.html
Granted, that's a four year old article, and even Leo the Tech Guy didn't know all of the things that we were doing at the time to improve the performance of solid state drives. (The company I was working for back then was developing various optimization tools. Note that I said
optimization, not
defragmentation.) These days, there are ways to optimize a solid state disk, and I know some (if not all) of the SSD manufacturers are building the optimization technology into the devices themselves. On the flash memory of a smart phone though, I don't believe there's any internal optimization happening, and as far as I know, there aren't any utilities available for consumers to do it themselves.