I've been experimenting with this and I'm quite impressed being honest. There are times that you might not need a full sized raw file, but want smaller file sizes. The space savings are huge v normal raw files.
And it's difficult to spot any differences from normal raw v the lossy ones. I can see very slight pixel differences at very very high magnification (very minor and not likely to be noted in print).
Lossy dng is a winner in my view. And yes I've made prints from lossy dng's and I can't tell the difference v uncompressed raw.
I know some will argue against it, I'm not saying I would use it for all work projects. But I'm struggling to see any notable differences for most work flow situations even low light shooting. Never been a dng fan much myself, but this is quite impressive really. It has practical and positive applications esp for higher volume work situations such as weddings and events. Yes you retain the ability to control NR, recover highlights and adjust WB just like a normal raw file. I think it's something many should check out.