The topic is explicitly about writing an SDK for the company's product, which is presumably intended to be imported in customers' code and used alongside hundreds of other libraries.

As such, writing idiomatic code for the language of the SDK really should be a concern, rather than implementing some idiosyncratic half-baked version of Go or Rust error handling in Python.

And GP is pointing out (correctly) that most of the time being idiomatic has more net gain than any putative advantage of the non-idiomatic proposal. Exceptions to this are extremely rare.