There is certainly some additional complexity here over the basic Lambda serverless setup. But I think the console-driven configuration as outlined in these posts often makes it harder to see what the core concepts really are.

With infrastructure-as-code tools, this can be a little clearer. At Pulumi we wrote a post earlier today on configuring the infrastructure needed to use EFS with Lambda, and it boils down to just a few concepts and a couple dozen lines of infrastructure code.

https://www.pulumi.com/blog/aws-lambda-efs/

Some of the complexity here also comes from the fact that EFS is a general purpose managed NFS service, instead of a fully-abstracted Lambda-specific feature. That does add a little additional up-front complexity, but means you can use EFS across all sorts of different compute in AWS - not just Lambda.

I retooled a step functions CloudFormation template to create and attach an EFS filesystem to four functions. Took about 25 lines of YAML.