Sitecore Best Practices (V10.1) 006 - Helix should be everywhere, even for dictionary, settings, core etc.

There are a list of benefit of using the Helix, like keeping the module separe, upgrade point of view and so, It's highly recommend  that to create the Helix structure.

Example, If we wann add a new dictionay enty which is specific to a feature, Plesae create the proper folder structure as example below

Sitecore/System/Dictionary/Feature/ABC (Module Name/ FeatureName 

Same for the Core database.