Jurgen wasn't fussed on buying Robertson. He wanted Benjamin Mendy (!) who went to City, Ben Chilwell (who was 17-odd at the time so seen as one for the future), or Alex Sandro at Juve (too expensive). Robbo was a scouting team recommendation, and was only signed after we missed out on Mendy because there was money left in the budget and Jurgen was OK with spending it so he'd have some cover for his first choice, Alberto Moreno. And we all know how that worked out.
Against that back-drop, Robbo was not only great value, but a massive upgrade on all the alternatives.