Can you set parameter defaults via Hiera in YAML Bolt Plans?

Question

When writing plans in the Puppet DSL I can use a Hiera lookup to assign a default value.

plan namespace::myplan (
  String[1] $user = lookup({'name' => 'namespace::user', 'default_value' => 'root'}),
)

Is it possible to transfer this to YAML based plans? E.g.

parameters:
  user:
    type: String
    description: The user
    default: "<something>"

My motivation is to (optionally) reduce the number of CLI arguments by allowing them to be set in Hiera instead.