In the beginning, there is JPEG and RAW formats. It was always known that for those who engage in the pursuit of digital post-processing, the RAW format offers more depth and flexibility. For those who don't, it is always best to keep both a JPEG and RAW file so upon retirement, there is something in the bank to work with.
When one opens the import module on Lightroom, there is an option called "Copy as DNG". So what is this "dng bet" business? It is the Adobe proprietary image standard that encompasses univeral compatibility whereas the Canon RAW or Nikon RAW are specific manufacturer's proprietary format. To understand further whether one should convert their file storage into DNG or keep as-is in RAW format, please read the following article explaining the differences:
http://photographylife.com/dng-vs-rawGood birding and photography.