Blender Cycles - Significance in 3d Game character, architecture creation?

Title of the thread conveys the main part of the question. I want to know, for someone who is creating game 3d graphics in Blender, what role does Cycles play in it?

Forgive me if this questions sounds too naive, but I am not too familiar with the cycles stuff and just want to know more so that I can decide if it is worth investing time in getting to know cycles better.

Thanks in advance for any helpful replies

Edit: Just to add to this, I once did try out cycles and since it did not allow render baking, I was put off by it and my curiosity ended there.

cycles needs ALOT more time per frame then a game could endure. on a mid class system the standard scene (this 2 monkeys) about 30sec. on a gpu (depending on the GPU and the materials). a pc game runs at 25-60 fps that means about 40ms per frame not 30sec.