Health Checks: Load balancers monitor the health of instances and only route traffic?

Short answer: to healthy instances. For example, when you have multiple instances of a Payment Service, the load balancer ensures that the traffic is distributed evenly, preventing any single instance from becoming a bottleneck.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.