Full Answer
GA4 for convenience, BigQuery for ownership and AI readiness. Use both for complete coverage.
Both. GA4 for standard reports, BigQuery for custom analysis and AI. GA4 limits: 14-month retention, data sampling, Google owns data. BigQuery: unlimited retention, unsampled, you own data. BigQuery is insurance against platform changes (remember UA sunset?).
GA4 for convenience, BigQuery for ownership and AI readiness. Use both for complete coverage.