what are the advantages vs disadvantages of using matrix items? is it possible to remove existing parent>child matrix items?

Perfect Ezample is Tshirts if you hhave tshirts you are selling then you dont need 4 diff item records called small, Medium, Large, XL and then have colors called blue, red, green, yellow for each size. this will result in 16 diff item records if created individually or 1 matrix item record. where you can update all the information in 1 place if you need to.