What makes borosilicate glass better?

Most glass baby bottles on the market are made from soda ash glass, one of the cheapest types of glass commonly used for soft drink bottles, jam jars, etc. Because it’s brittle, it has to be made thicker and heavier. It also has a low thermal shock resistance meaning it will likely crack when transferring a hot meal to the freezer or pouring hot/boiling water onto it.
Borosilicate glass is a superior glass commonly used in science labs (think test tubes and beakers) purpose-designed to store extremely hot and cold liquids with ease and be tough and crystal clear. It is inert and will not hold any odours, is scratch-resistant, won't stain or easily house bacteria.