Smyly is more akin to Lively, Eflin is a young pitcher putting it together, he had two extended runs of excellent pitching, with a black hole of July inbetween. His strong finish wasn't a fluke.
Smyly is definitely worth bringing back on an incentive laden deal, that's how you build depth, stockpile arms and hope a few emerge. If the Phillies were coming off a 90+ win season, it might be time to roll the dice on a mega-deal for Cole, but he's not going to make them a winner (no pitcher does that), but he could put a winner over the top. This offseason I'd just focus on adding arms, and hope you get lucky and land someone else's Morton (veteran who bounces back).
Hopefully Klentak has learned his lesson on veteran RPs, either go big (get the best without too much mileage) or go home, that is, guys at minimum cost provided as much value as Hunter or Neshek or Robertson.