Data transfer pricing

Hello,

When using Cloudflare Workers, there isn’t data transfer charge (as far as I know).
When using Websockets with Durable Objects, there is a data transfer charge of $0.09 per GB (after beta finishes). This makes the Durable objects much more expensive than Workers.

Did I misunderstood the meaning of Data Transfer charge on that product or indeed Durable objects are more expensive to run and therefore data transfer charge needs to apply ?

Regards,

Janusz