BTV is a pretty pure calculation, though. It's based on projected WAR and salary, right? And it's only for 1/3 of a season. A star player might have a projected WAR of 1.5 to 2 for 1/3 of a season.
What's left out of the calculation is the postseason value of the player acquired. Because that's often a big part of the equation. Like when Theo traded Torres for Chapman.