Are Unity 2D games actually 3D games?

Hi guys,

I am completely new to Unity, yet I want to develop a 2D mobile game.

After watching a few videos I am a bit confused. It looks like you create a regular 3D game and just set the camera to orthographic to make it look like a 2D game.

Is this actually the way you develop 2D games in Unity? I mean that sounds like a lot of wasted resources if you have all models and stuff in 3D where simple 2D images (sprites) would do.

Probably these guys are just doing it wrong?

Any clarity...

Are Unity 2D games actually 3D games?