1) Yes: I can and do play MC FLAC files via a USB drive or portable hard drive plugged into my Oppo 103. Some of these files I’ve purchased, usually from eClassical.com, others have been shared with me. I regard FLACs as a decent enough substitute for SACD, but not for DVD-A or Blu-Ray, as I miss the menu screens and assorted extras.
2) Like others who've answered the poll, I have no real incentive to burn FLACs to disc—although I do have the capability, via the above-mentioned HD-Audio Solo Ultra.
3) I still have a preference for physical media (with booklets, artwork, etc.), but I have plenty of FLAC and DSF files, too.
P.S.: If labels started releasing more out-of-print or never-before-released MCh music as download-only--either FLAC or DSD--and at reasonable prices (say, USD 12-20), then I'd buy as much of it as I could afford to! So far, though, way too many online retailers catering to audiophiles are selling digital downloads at prices higher--sometimes far higher--than their physical-media equivalents. I don't get that at all....