> It's not easy, but it's their work.

There's a significant asymmetry though, it's not just a bit more work. I'm a bit cynical here, but often it's easier to just overengineer and be safe than to defend a simple solution; obviously depending on the organization and its culture.

When you have a complex solution and an alternative is stacked up against it, everything usually boils down to a few tradeoffs. The simple solution is generally the one with the most tradeoffs to explain: why no HA, why no queuing, why no horizontally scalable, why no persistence, why no redundancy, why no retry, etc. Obviously not all of them will apply, but also obviously the optics of the extensive questioning will hinder any promotion even if you successfully justify everything.