Normally, in a game there is a completely separate not-awful-looking GUI system for the player, pushing Dear ImGui towards the opposite niches: simple in order

Normally, in a game there is a completely separate not-awful-looking GUI system for the player, pushing Dear ImGui towards the opposite niches: simple in order to be easy and efficient to write rather than complex in order to be general and flexible, evolution through changing (mostly adding) widgets and assimilating more data rather than through improved appearance and behaviour of a relatively simple and stable GUI, "just working" and low churn rather than configurable, cheap rather than accessible, and so on.