The figure in a landscape attracts the viewers eyeoffering a focal point and perspective for scale for the paintings composition. At the same time it offers the 'human element' transforming a scene or setting.
The figure or portrait demands tactical rigour and experience to understand the anatomy, a pose, an expression thereby offering a feeling, empathy or understanding of the form.
We cannot presume a landscape all painters possesses the same skill base or comfort with a figurative subject. The figure or capturing a likeness can often tell a story engaging the humanness, character or mannerism. A figure in landscape gives a context to a composition it also can enhance or detract from the composition overall. A professional artist will of course strive to achieve the former. The expressionist approach of capturing the figure could be another avenue artist seek in their endeavour to draw out the form or simply make it appear as an individual or part of the overall composition.