Oh wow no I must have misstated what I meant. I turn jpegs into lossless PSD as I process, which is similar to a TIFF format image except photoshop proprietary. Add layers to it, and that image size multiplies, make it 8 layers and its a good 160MB. If I process a RAW the same way, its even more, but at that point the only real difference is 8 bit vs 16 bit, as they both then become lossless files. 99% of printing is done in 8 bit already, so even processing RAW, I often convert to 8 bit.
Heres another problem - processing jpegs, and re-saving them as jpegs, every time you save as jpeg, the image goes through yet another compression routine and degrades the image. Time after time after time, it can have a very negative impact on the image.
I really didn't like lightroom, I found it a mega resource hog, and the way it tried to autofetch files so often was just obnoxious for me. Image data converter is efficient but simple, it offers me all I need in raw processing. Personally all that is done in lightroom I think can be done better in Photoshop, I see lightroom as an 'Image data converter' with pointless fluff. Image data converter does all I need with raws, photoshop handles the rest.
Now I understand that it's the processing.
Layers add a whole new dimension to the world of processing, ever since I've used overlay high pass filters, I havent touched smart sharpen or unsharp mask.
People who use Lightroom have more than enough room to spare for the relatively tiny RAW files that are in contrast to 60-120MB JPEGS.
Lightroom adjustments are very cursory in comparison to layered adjustments. This isn't where lightroom has the edge.