A teacher once told me that Lightroom was a cheaper, easier to use, simpler version of Photoshop. I said, then why do I own both? Why does Adobe sell both of them together? And why would half of the raw-shooting*, professional photography community recommend the software? Because it serves a different purpose. The people over at Adobe took a misstep in naming Lightroom "Adobe Photoshop Lightroom." This gives it the appearance of being some other version of Photoshop Elements (which is actually a cheaper, easier to use, simpler version of Photoshop). The whole reason for Lightroom's existence is because of raw. Back when the capability to shoot raw emerged, photographers didn't have a way to fully utilize the data that they had.
*Raw is a type of file format. Raw pictures capture more data than a compressed file would, so you have more power over the final image in post. JPG is compressed. DNG is raw.
Every photo I take is raw, and I always edit in Lightroom. To see what amazing changes can be accomplished with Lightroom, look below.