He's averaged just 3.9 (BBRef) or 4.3 (Fangraphs) WAR. Fangraphs rated him much higher this past year, 3.5 to 1.3, and projections say 4.8 this year.
If his defense bounces back and/or he moves down the defensive spectrum than it could rise, but I'm not expecting more than 4-5 WAR on average for the next five years. Presumably CBP means it will definitely trend higher (don't know if projections have been updated for that?). But could still be 7 one year, 3 another. Even in 2017 when he had a 1.008 OPS it was less than 5 (from both sites).
He doesn't have to repeat 2015 five times to be worth it, and the Phillies still didn't (and don't) have anyone that good.