There is something particularly conceptually wrong with throwing away the stuff that comes out of your camera. If your camera shoots in DNG, then that's what you work with. If it shoots in RAW, the same. If it shoots in either, you have to figure out what the difference is in terms of metadata that is supported, as well as all of your workflow.

When your camera shoots in its own proprietary RAW format, and you convert that into DNG and throw away the former, you're essentially throwing something away and the sad part is that you probably don't even know what. It's like shooting in color negative film, and have the lab contact print that into color positive film, just because you're scared that someday your scanner will no longer scan negative film anymore.

If your workflow supports your proprietary format today, there is no reason to think that it won't support it tomorrow. So what is the net benefit of converting it into another proprietary format that is simply 'open' because Adobe has published the specs? That whole open/closed thing doesn't matter. What matters is the tools that you use and how they support them.

I've made the mistake of converting and throwing away the originals, and I did learn the hard way. I didn't lose any shots, but I lost my freedom to use them in the tools that I wanted, because those tools didn't support the DNG as much as I wanted to.