That's not objectively true. It's a philosophical question and it depends on how you value or think about things like true talent vs. production, ERA/RA9 vs. DIPS, projection vs. results, WPA vs. unleveraged linear weights, etc.
There is certainly an argument to be made that WAR underrates elite relievers because of WPA considerations BUT is Kendall Graveman an elite reliever? Projection systems still think he's barely a good reliever.
When you say something like "is having a better year" the rebuttal is plainly that he is probably just getting lucky in high leverage situations. So it's up for debate.
Anyway, I think Seattle was wise as hell to cash in and they got a massive value in return in Toro.
The point of my OP was not to compare 2021 Graveman and Liriano in context, but Houston obviously thought Liriano back then had big value. Or they just thought Teoscar was a lost cause. Maybe they think Toro is a lost cause now. Who knows.