Mostly the advantage would be that 1) you wouldn't have to maintain the buildpack yourself, 2) operators can upgrade your software without needing to get you to

Mostly the advantage would be that 1) you wouldn't have to maintain the buildpack yourself, 2) operators can upgrade your software without needing to get you to do it, 3) upgrades might actually be faster due to layer rebasing and 4) if you add other stacks to your architecture, you still have the same development, deployment and update experience.