Explicit Hierarchies in Microsoft's Master Data Services was always a curious feature. Yes, it enabled you to create a hand crafted hierarchy, but why? For example, in the sample model for Product, the Product entity (table) has a product category and subcategory hierarchy based on two entities (tables). A table, or in the case of MDS, an entity, is a more data architect friendly way to organize. I'm sure there were some benefits to hand-crafting an explicit hierarchy, but I have found that table based structures are the preferred approach.
Starting with SQL Server 2016, the Microsoft Master Data Services Blog has posted that explicit hierarchies and collections have been deprecated. It seems they have enhanced Derived hierarchies to the level where Explicit hierarchies are no longer needed. See: Deprecated: Explicit Hierarchies and Collections.