You need data but everyone has it. It's not really about using data, it's about the analytical skills of the person. It's not like everyone having access to the same data will come to the same conclusion. Everyone will spot different patterns, highlight different aspects and interpret it differently and thereby reach different conclusions. It will always come down to analytical skills as what separates managements. Scouts are needed to find and validate talent, data can help get another picture or to reject/confirm/complement analysis of the scout. Scouts will never become obscure because they can see talent masked in data points or they can, having a complete picture of the club and contemporary needs, find solutions that can be complicated to find in data points. Same can be said with data but coming from a different end and from "knowing what to look for" for a specific problem. But even then you will need the scout to confirm/reject/complement that picture.
That is my take in a short version. Both are needed.
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I could add, which I can only speculate in because I do not know how this works in reality. But I would guess scouts also help establish relationships to players/agents/clubs.