Generative Shape Fill Beta and Mockup Beta

I have two questions in one post:
1 - I was wondering why there is a T-shirt image at the splash screen of Illustrator. Please review the image. I got the Generative Shape Fill (beta) part but why there is a tshirt image next to it? Can we mock up a vector image directly in illustrator or do we still need Photoshop to do this? 

2 - ALSO: MY SECOND QUESTION IS
I brought a Tshirt Image and created an AI vector image with Generative Shape tool. I tried Mockup Beta by selecting both the tshirt image and vector image I just created. Although the vector image wrapped around the T-shirt well to arm, as shown in the second image I have uploaded here, it does not work well with wrinkled T-shirts. It is not realistic. The wrapping part works fine but I was expecting this to work on wrinkled tshirts more realistic.