What benefit would a low airspeed system have?
Apart from better data for weapon computation I can only think of one advantage:
For once we can fly the sometimes funny CAT A procedures, which are based on airspeed and not groundspeed, acurately by the numbers.
Not that it would allways make sense though. An LDP of 25 knots with 30 Kts of wind would still give you a groundspeed of minus 5, what somehow defeats the purpose, but that is a different topic.