Any lens can be used for any purpose under any conditions.
For my use, the 85mm 1.8 was generally a walkaround and portrait lens that also did landscaping for me because of the high resolution when stopped down. I sold it to purchase a 50 1.4 because it was a focal length that I liked better, and I already owned a 70-200 2.8L IS. I do miss mine, though.
Great lens, fast and accurate focus, small and light package, very resistant to flare but very bad chromatic abberation control (purple fringing).