[brodouevencode]

Importing code paths that are never executed in a service is a security risk at best, a development/management nightmare on average, or an application crippling architectural decision at worst, especially when working with large monoliths. That is not a smart trade off - I would not recommend this pattern unless the cost to break off is so exorbitant that this would be your only choice.

[JohnBooty]

For a monolith of any nontrivial size, you're talking anywhere from weeks to months of years of engineer work, and those are engineers who also won't be delivering new value during that time. And if other teams are still delivering new features into the monolith during that time, now that's more work for the team whose job it is to break apart the monolith.

So anywhere from tens of thousands to millions of dollars is the cost.

Whether you call that exorbitant is up to you and your department's budget, I guess.