Microsoft has accounced Premium plan for Azure Functions who need to enterprise serverless workloads. This is newest Functions hosting model. This plan enables a suite of long requested scaling and connectivity options without compromising on event-based scale. You can run on more powerful instances.

I think this is the most important for enterprise segmentation who needs to VNET integration for functions. Premium plan has supporting the VNET integration.

See below of comparison of how the Premium plan improves on existing dynamically scaling plan, the Consumption Plan.

Advanced scale controls enable customized deployments

Instance size can now be specified with the Premium plan. You can select up to four D-Series cores and 14 GB memory. These are substantially more powerful than A-series instances.

Connect Functions to VNET

Premium plan allows dynamic scaling functions to connect to a VNET and securely access resources in a private network. This feature was previously only available by running Functions in an App Service Plan or App Service Environment and is now available in a dynamically scaling model by using the Premium plan.