Lightroom is vastly more-efficient at handling many images than Photoshop ever will be. If you are doing "photography", Lightroom is the answer for many people. If you want to convert two or three or four RFAW files out of every one hundred, there are many standalone RAW developers that work well. If you want to do photo-illustration, Photoshop has the pixel-level editing advantage that most other applications lack.
Just to comment on what might be a little misleading about the term -
photo-illustration.
Lightroom is excellent at managing images and at doing global changes to an entire image or group of images.
It is rather clumsy at doing changes to very specific areas and doing complex editing because of its inflexibility in selecting areas and then managing the selections.
If I want to change the brightness, contrast, sharpness etc in specific well circumscribed areas, it is possible to do this in LR but it isn't possible to manage those changes individually retrospectively because LR doesn't have a good mechanism to separate the edits.
When I am done with a complex edit, doing lots of different changes in lots of different places, I can look at the PS file and make change in each of those edits no matter where it is in the process - early or late. With LR, edits are piled on top of each other and you can step back through the process (if step 4 was wrong, you can remove steps 10-4 and redo them all; PS allows you to go to any step and edit only that one)
Flexibility, degree of control and variety of edits available are just not available in LR. For that reason, high end retouchers don't use LR.
Where LR is particularly poor is in selective sharpening and I usually sharpen in some other application, mostly PS.
If you usually do just global edits and don't need the control of PS, LR will do it for you.