Agree with most of that, but I will just point out that there are multiple ways you can do data-driven signings. If a player is a superstar and all the metrics point to him making an impact in the side, then he's the data-backed candidate, even if he costs a lot.
The way we seem to think of data-driven is more in 'identifying value' - i.e, the player who would most benefit us is too expensive, but here's a player who meets some of the metrics while being cheaper. So, 'greater value'.
The motivation behind employing 'data-driven' scouting matters. If your aim is to use data to build a great side, that will show. If your aim is to build a cheap side, that will show too - be that cheap in terms of transfer fees, or (more pertinently) wages.
Since we only have a small sample size and none of us really know which players we were looking at and what metrics were considered important, it's really easy to make an argument for whatever you want. I think we've overpaid considerably for some of the players we've brought in, but maybe they were ones we really wanted.