Can someone explain what 'diskutil cs revert' does?
diskutil cs revert turns off the Core Storage volume manager for that volume. The Yosemite installer turns it on in case it's needed later (mostly for FileVault), but if you don't actually need it (e.g. for FileVault a Fusion disk) it doesn't do anything useful.

If you aren't using FileVault or a Fusion disk, what Core Storage mostly does is confuse Disk Utility, limiting its ability to dynamically resize and rearrange volumes, and preventing it from displaying the disk structure properly. That "251 GB APPLE SSD SD..." thing is what Disk Utility should be displaying there, because "Macintosh HD" and "BOOTCAMP" are both volumes within the physical SSD. With Core Storage, it was showing BOOTCAMP as somehow part of Macintosh HD, which it isn't at all.