Sitting crossed legged is a posture that I choose often, on the ground, on a couch, in an office chair and for meditation. I find the position to be most comfortable for me to stay still for a period of time. I realize the posture is not available or comfortable for everyone (it does improve with practice, I promise), however, getting down, sitting on and getting up from the ground are movements we want to cultivate for healthy spine, hips, knees and ankles.
In addition, I have learned through my studies in yoga that siddhasana (essentially sitting crossed legged on the ground), as referenced in the Hatha Yoga Pradipika and Light on Yoga is one of the most important postures we can practice. The posture allows us to have a long spine with optimal relaxation throughout the rest of the body. Sitting tall gives us better awareness and alignment to our subtle energy, so we can be a meditative state. Taking a few minutes to sit cross legged on the ground, on a block, on cushions and bringing our attention to our breathing is a meditative break we can practice daily.