Payment / Pass: Without this → duplicate charges, user lockout, revenue loss
Fare / Pricing: Without this → wrong fares, user trust erosion
Circuit Breaker: Without this → one slow provider crashes search
GPS: Without this → wrong pickup/drop, failed rides
QR: Without this → tickets fail to scan, riders stranded
Safety: Without this → safety gaps, trust risk
Booking: Without this → booking failures, lost conversions
Cancellation: Without this → drivers cherry-pick, riders wait
Monitoring: Without this → issues undetected until users complain
Kafka: Without this → message loss, data inconsistency
Tests: Without this → regressions ship to production
Perf / Optimize: Without this → higher latency, more infra cost
Accessibility: Without this → unusable for visually impaired
GHC Warnings: Without this → technical debt compounds
Docs / Playbooks: Without this → ad-hoc incident response
Allocation: Without this → unfair ride distribution, driver churn
Onboarding: Without this → driver registration friction, supply loss
Settlement: Without this → drivers don't get paid correctly