Reduces latency when the cached content is served from a local cdn pop, allows you to absorb some level of DDoS, can absorb traffic spikes more easily so infra can be more static, reduces load on server if assets are dynamically generated on the backend but can are cacheable, some senses can lead to simpler deployment as you serve assets from an object bucket, so no need to deal with keeping that data in your cluster, but that's minor. There are downsides too, cost, over caching, privacy/security perhaps too.