Issue the following command in your OSGeo4W Shell.
pdal translate ^ c:/Users/hobu/pdal/exercises/translation/interesting.las ^ c:/Users/hobu/pdal/exercises/translation/interesting.laz
LAS is a very fluffy binary format. Because of the way the data are stored, there is ample redundant information, and LASzip is an open source solution for compressing this information
Verify that the data are in fact compressed: