Watches - performance

I’d like to obtain some information about watches feature in Consul. Let’s suppose I want to have a custom set of KV watches on each host in the cluster. And my question is, how it could affect cluster as a whole when I have up to 2000 nodes in a single datacenter. If I understand correctly, each agent performs periodicall requests to fetch changes in the KV. I’m afraid such amount of traffic could put too much load on the servers since KV endpoint doesn’t support local cache.