Why is HF (High Frequency) radio still utilized for air traffic control communications in oceanic and remote terrestrial airspace?

1. HF signals bounce (refract) off the ionosphere, allowing long-range, over-the-horizon communication.
2. HF provides static-free, crystal-clear digital voice data links.
3. HF antennas are very small and easily fit on small aircraft.
4. HF is immune to solar activity and electromagnetic storms.