hello, RealityCapture is focused on mesh and there are tools dedicated to this purpose,
you can filter your mesh selection (using the Lasso, Rect, Box and/or Advanced tools + the Filter Selection tool - all accessible from the RECONSTRUCTION tab) and export the newly created (filtered) model as a point cloud (ALIGNMENT tab / Export / Point Cloud),
if you need a sparse point cloud, you will need to extract if from a preview mesh created using the default settings