That's irrelevant, FLAC is an archival format. If you rip a CD, it makes perfect sense to rip it to flac in order to have no data loss whatsoever, and be able to fork it off to whatever lossy format is de rigueur for your new device. If you rip to a lossy format, then each copies will accumulate approximations from the different codec's perceptual models, especially if you keep deleting the previous copy and only keep the new one.
I don't put FLAC files on my phone, it takes way too much space, and the phone doesn't support it anyway. The phone gets AAC conversions of the "master" FLAC files.
Besides, the quality of 256 VBR won't be the same as 256 CBR, but with FLAC, there's only different compression sizes.
Server storage is relatively cheap, mobile storage is a different kettle of fish, and even with a lot of storage, if you have a large music collection it's much easier to blow way past with FLAC as it's at least an order of magnitude larger than even high-quality lossy tracks. I can't put my entire collection on my phone even after having converted it to a lossy format, putting the lossless masters is plain not an option.
And since conversion is easy to do, and to automate, really the only reason to put lossless tracks on a device other than the storage server where they live is sheer laziness.
A decent proxy to know that this is true is that at those bitrates, a FLAC file is often smaller than the AAC one. Yes, this makes you wonder why you'd want to use an lossy format instead of the lossless one if you have the choice ... but the point is that you'll probably have just as good an experience with a high-bitrate lossy-encoded file.