Can Unity support / use textures that are not square?

Can Unity support / use textures that are not square?

I have been told by another highly skilled Unity artist that Unity cannot efficiently handle non square images. Since that doesn't sound right to me, I wanted to get a second or third confirmation to that claim.
Having worked in the game development industry for almost 15 years, I have always understood that best practice was keeping in powers of two, but that if the UV map called for it, a 1024x512 map was acceptable, rather than using a 1024x1024 map with 1024x512 pixels of wasted UV space. Granted, that was best practice on game engines other than Unity.
Can anyone confirm that in Unity's case, it is better (best practice) to have a 1024x1024 image containing UV islands occupying 1024x512 pixels, rather than using a 1024x512 image map to exactly accommodate the UVs?
Which platforms can use non-square images and which ones cannot with the Unity engine? I am particularly interested in whether or not this limitation affects PC builds.

Solutions/Answers:

Answer 1:

Yes, it can. But certain devices will suffer. For example, iOS PVRTC texture compression doesn’t work without square textures. I think Unity makes them square, so you end up with your textures taking up a bunch more RAM to accommodate PVRTC.

See Unity Documentation: 2D Textures for more details.

References