Ornate mecha goes hard because mecha is essentially a sci-fi way to reintroduce legendary warriors to the battlefield. It's a vehicle to bring back the type of fighting men immortalized in history pre-industrialization. Like WW1 fighters it's a rebirth of the cavalry

Mecha, alongside other genres, is a result of the masculine spirit's desire for close, personal combat. It works so well for the same reason combat sports like boxing and MMA do. Unlike modern warfare, which is detached, combat in mecha is very personal

Take for example Gundam and VOTOMS, both considered classics in the real robot genre. Despite being 'real' both series focus heavily on the life-or-death competition between the protagonist and antagonist(s). VOTOMS peaks with Chirico and Ypsilon.

Not just Gundam, but all of Tomino's mecha anime gets this down. The fights are full of dialogue and plot, and the rivalries are usually satisfying. Cutaways to the pilot help reinforce the close, personal aspect of the writing

Think of the mecha as suits of armor. Just as knights of old were able to survive battles because they were protected by heavy plates, mecha pilots are likewise shielded by their machines, but they can also eject in emergencies, and lose limbs and yet come back repaired.

The machine is humanoid for this very reason! It allows us to relate more with what is simply a machine. The mecha is an avatar of the pilot, allowing for the pilot to fight tooth-and-nail and even be defeated without dying; enabling rivalries to persist