We considered confluent at my last job, where our throughput was going to be miniscule to start but we required VPC peering...that bumped us into an Enterprise plan for something like 80k/year! Went with Aiven instead which was more like 20k/yr IIRC.
The trouble is if you need VPC peering then it requires a dedicated VPC, dedicated k8s, dedicated instances. Confluent currently only offers one instance size, so that dedicated offering can't be scaled down.
PrivateLink allows for shared VPC and hypothetically a shared k8s. So the cost structure can be better on the Confluent side. Of course scaling down instance types would make a huge difference, but I don't think that's supported currently. The cheaper option is multi-tenant Kafka clusters.
In general, I think VPC peering is a dead end for use cases where you are connecting two companies networks together. It's not great operationally and puts a lot of security / filtering burden on each party.
I'm not too knowledgeable about all this, I'm sure you're right, and it was someone else's requirement that we have peering. Still, we'd grown accustomed to other vendors offering it by default (Timescale Cloud, Aiven) so it was a serious sticker shock and a big part of making us go elsewhere.
