Missing <class> in Mage_Core Helper Factory Declaration

[Sdfendor]

I'm currently working on a module creating Advanced Metadata to be used e.g. in PHPStorm or the language server Intelephense.
During test runs I noticed missing definitions for the helper factory route core (e.g. core/data, core/js) in the output. The reason for this I found is, that the route declaration in the corresponding config.xml is missing the class element:

The factory method (Mage::helper) or rather the core config model has a fallback built-in making it work without the class element present. The Magicento plugin resolving the factory routes on the other hand can't handle missing class elements.
I looked at every helpers element in the core modules, and Mage_Core is the only module for which this is the case.

My question simply is if anyone knows a (historical/legacy) reason for this and if there could be any drawbacks to just adding the missing class element. If not I would prepare a PR.

[Sdfendor]

In the meantime I realized that this fallback is in more widespread use than expected when I wrote this question. So I implemented a way to deal with the fallback logic without the need for complete definitions in the factory nodes (helpers, models, blocks).
With that realization I can answer this question with "it's optional" to myself.