maybe this is a pretty broad question 😀 The short answer is that you can add/remove brokers easily as they are stateless

You can easily add new bookies

When you drop a bookie you have to “decommission” it in order to ensure that the data that was on the bookie won’t be “underreplicated”

usually you don’t need to scale zookeepers dynamically

proxy/function workers are stateless, so you can scale them whenever you want

I hope that helps