Mark T. answered 03/17/19
Career nuclear engineer, professional instructor, Lightroom expert
It's a complete photo management system. If you find yourself spending time looking for pictures on your computer then LR likely will save you time.
The Develop Module is 1:1 nearly exactly ACR. It actually does the same exact edits using the same coding.
But, imagine a complete photo management program tied into doing ACR-like edits. I can image you can see how efficient that would be to editing lots of photos at once.
Plus I prefer to round trip to PS from LR. It manages the files seamlessly.