This is essentially the same tension between static and dynamic typing.
No matter what, all bug free code is complex. Correct code can be written in any paradigm.
But productful code ships with bugs.
Does test user creation need to be bug free? I don’t know. It feels like something where productful test user creation can ship with bugs, even if in reality your test code harnesses should not be buggy.
You can step even further back and ask: when you have essentially unlimited resources, why ship buggy code at all? Netflix has unlimited capital, and it isn’t in a hurry anywhere. Engineers should never choose productful over bug-free. You learn nothing (Netflix’s product problem will never resemble your startup’s product problem) and you forfeit the opportunity to learn (ReactiveX is a good, expressive paradigm).
This is a startup forum, is this true for startups? IMO, yes. Your startup is going to fail. You will not learn valuable product lessons from the journey. I mean people certainly pretend and say they do, but even in the situation of success, Brian Chesky still hasn’t become Walt Disney last I checked. But once you have enough money to be employed for a year, as an engineer, you know, fucking learn how to do something the right way, bug free and performantly.
So I agree your coworkers are fundamentally making an error.