Question about architecture

We're in need of a content entity import/export mechanism for Commerce, so I decided to look at the existing solutions (default_content, yaml_content, demo_content).

My own expectation of the export flow is something like this:
1) Entity is exported to an array ($entity->toArray())
2) Field data is normalized based on the field type
3) The final structure is exported into YAML
And import is the reverse.

This is precisely the use case for the core Serialization module. It has a normalizer architecture, and encoders.
The normalizer architecture is unpleasant (due to the way its tied to the format), but that's a well documented complaint (#2575761: Discuss a better system for discovering and selecting normalizers).
No YAML encoder exists in core, but one could easily be provided.

So, looking at the module, I was surprised to see it relying on HAL, one level above the Serialization module.
The information added by HAL (_links) seems to be pure noise for the import/export use case. Furthermore, it's JSON, which doesn't match the default config YAML. Is this decision documented somewhere? Or was it done purely from a code reuse perspective?