Yes, it protects fabric. You would spray it on any fabric or carpeting in the car. I believe the original product name is spelled "Scotchgard".
It is produced by the 3M company, famous for its product "Scotch tape". (3M comes from Minnesota Mining and Manufacturing.) I'm guessing that the use of Scotch in Scotchgard is an attempt to leverage the public relations gains they had made
Yes, indeed. Where I live we have discount stores where goods can be bought quite cheaply. The name? McFrugals. ('Mc" and "Mac" are common for Scottish surnames - and Irish).