The paper seems to go into this.

* There is no generic way to say whether a defer should free up a variable based on the value it has when the defer was encountered, or a potentially-different value the variable might have when the defer is actually run. * So the best thing to do seemed to be to give the programmer the ability to make the choice. * Lambdas are the means they chose to make that happen.

But this all seems to stem from a desire to enable a use case beyond what an obvious use of a goto idiom would support.

Because there are multiple defer proposals and this one is made to be compatible with the lambda proposals. N2589 for example proposes a simpler defer statement that just defers an expression, so e.g. "defer fclose(f);"

Huh that's a good point.