Exporting as "original" does NOT include the edits, it just exports a copy of the original file with an XMP file that contains the edit instructions. These XMP edit instructions are only useful in Lr and Photoshop. If you want the edits from the RAW file you have to export as tiff or jpg. You stated at the beginning that the nef rendition is better than the jpg so why would you consider using jpg?
O, I got it. Thank you Bob. I tried to save it as TIFF, but the file became too big. Thus, if an initial NEF was about 25MB, then after conversion in TIFF it became 220MB! The only one advantage was that it retained all the edits. I also exported the NEF file as JPEG, however it appeared a bit smaller than I expected: 12MB out of the initial 25MB. When I shoot in JPEG with maximum resolution of 24mgp, a file's size is about 22-25MB and apparently has less losses that converted from NEF 12MB file. So, long story short: the dilemma is to choose in what format keep shooting. And the main reason is to be able to open it up after editing in any image viewer like Photo Gallery or MS Photos. Now after your feedback I am leaning towards JPEG with max resolution.
Bob, I appreciate your information. Thanks again.
JPGs use lossy compression so some pixels aren’t exactly the same anymore; however, if you use the highest or close to highest quality setting in LR during Export it will be hard to tell any difference.
JPGs are compressed by contain 3 colors per pixel whereas raw files (NEFs in your case) usually contain only one bit per pixel and are compressed in a way that makes them smaller but doesn’t lose any image data.
TIFs if not compressed are the width x height x 1 or 2 bytes per pixel x 3 colors-per-pixel so can be huge as you have seen.
If you shoot JPG and edit those in LR you still cannot see the LR edits in those original JPGs, only the camera rendering.
In the TIFF export are you using 16 bit or 8 bit. As far as I can tell, 16 bit is only useful if you are going to process the file in another editor such as photoshop that supports 16 bit. As far a viewing and printing, the 16 and 8 bit TIFFs I have exported look exactly the same so I just use 8 bit TIFF all the time as it is lossless whereas JPG is lossy. The 8 bit file will be half the size of the 16 bit. JPG is always 8 bit from lightroom but compressed. Maybe one of the pros can answer this in more detail.
Gentlemen, thanks a lot for providing this explicit information. I am much more clear and educated now.