At what point do you actually need a data lake?

I see many startups immediately setting up S3 + Spark + Delta Lake even when they barely have 5–10 GB of data.

For smaller teams:

• Is a warehouse like BigQuery or Snowflake enough?
• When does a proper data lake start making sense?
• Is the lakehouse architecture overhyped for early-stage companies?

Would love to hear real-world thresholds (data volume, team size, use case).