Describe XuanxuanQijingProblem199/Attempts here.
There a number of cutting points for White where the continuation of a sequence depends on the aji by the threats made with each move.
This circled point is a sure way for White to get One eye (in Gote)... So this option is useful when White threatens to make two eyes elsewhere, Black responds, and so White can then play the marked space to get life and solve the problem. A move here doesn't seem to threaten anything -- so it looks 98% like a finishing move.
I am uncertain. Please add your variations if you think differently...