In practice, considerable difficulty. Like you said LEO moves fast. You are talking 10 min in line of sight (LOS) depending on the orbit. So the handoff algorithms (and necessary network) are very challenging and cost prohibitive. I mention it in my earlier response but if you have a LEO network you need pretty substantial arrays to accommodate such a power load, and during “night” for whoever is using the network, you need transfer mechanisms to relay the data, using even more power during eclipse. This is a real challenge.