With virtual copies I can edit however I want and still keep the original around for comparison.
I don't really see any great advantage to that. For me, virtual copies are for those occasions when I want two different edits of the image. Say, different crops or different color adjustments. I can always go into the edit history and roll back my edits to see how the original looked like (not that I ever feel the need to, though).
And the virtual copies exist only inside your Lightroom catalog file, that's why they're called
virtual copies. They only take up space when you generate a JPEG from that virtual copy.
The last point here, though, is a major paradigm shift when/if you start using Lightroom. I'm so old that I remember film (or "analog photography" as the kids call it nowadays. Now get off my lawn!). For me, the original camera file - be it raw file or JPEG - is like the film negative. You don't ever change that, you just process it in different ways. The edited image exists only in your imagination until you generate a finished JPEG. That's a brand new file, much like the paper copy made from the negative was a new physical image. So you never change or copy the camera file, you just give LR instructions about how to tweak the representation of that file when it makes a working JPEG for you. The generated JPEG can then safely be deleted from your harddisk after you've uploaded it, sent it to the lab to produce a paper copy or emailed it to your mom¹. The only thing that takes up space on your harddisk is the instructions in the LR catalog file about how that particular image should be post-processed. It's fundamentally different from editing a picture in Photoshop, or a letter in MS Word, and really understanding this different paradigm was the only thing I had to spend a little time to get used to. The great advantage, though, is that any edit you do is fully reversible (it's just instructions, right?), so the hassle of keeping copies of the different edits of the same image is avoided (IMG_123_Edit1, IMG_123_Edit2, IMG_123_Edit1_2, etc. And after two weeks you won't remember how you edited IMG_123_Edit2_1_3, even at gunpoint...)
¹ OK, I have to admit I don't follow that rule fully myself. I always generate one full-sized JPEG from each image I want to keep, and that JPEG is archived in another place than my original image files, to doubly ensure compatibility in the future. While the JPEG format is an extremely well established and almost universal standard, raw file formats differ between camera manufacturers and even between camera models from the same manufacturer. So I'm not quite sure that I'll be able to read my camera raw files a few decades from now, when software producers and camera manufacturers have come and gone.
