At the CTO and principal engineer level, add this question: what does this system cost to run at current scale, and what does the cost curve look like at 2× and 10× scale?
Compute, storage, network egress, and managed service costs all scale with usage. An architecture that is cheap at launch may be economically unviable at scale. The question is not whether cost matters — it always does — but whether the cost model is understood before it becomes a constraint.