Since libraries have different use cases and characteristics than normal app code they can and should be treated differently.
A 10% cognitive cost for code that is used by thousands of developers is a very high price to pay for an initial 3x speed boost to one developer.
A 10% cognitive cost for code that needs to be understood 3-10x before it effectively expires (like most app code) is a great tradeoff for a 3x initial speed boost.
I'll get my app in my customers hands in 3 months, wear a little "tech debt" on the dev side, and get crucial feedback. You can take 9 months to deliver a functionally equivalent app with slightly better internals.
Since libraries have different use cases and characteristics than normal app code they can and should be treated differently.
A 10% cognitive cost for code that is used by thousands of developers is a very high price to pay for an initial 3x speed boost to one developer.
A 10% cognitive cost for code that needs to be understood 3-10x before it effectively expires (like most app code) is a great tradeoff for a 3x initial speed boost.
I'll get my app in my customers hands in 3 months, wear a little "tech debt" on the dev side, and get crucial feedback. You can take 9 months to deliver a functionally equivalent app with slightly better internals.