If you like barrel-aged imperial stouts, then it's absolutely worth the premium. You can easily pay more for other stouts that aren't as good, IMO. I love big imperial stouts that focus on notes of coffee and chocolate and rate the KBS among the best that I've had.
Locally, KBS sells here for $23.99/4, but my local bev center put it on sale for $19.99/4 to blow out the 2018 vintage ahead of the 2019 being released this month. Backside of my grocery store receipts gave me an extra $5 off $50 there too. Needless to say, I stocked up.