There are several benifits to using glass.

Very low embedment

Glass has very low embedment less than 2%

Other abrasives such as slags leave 15% to 20% embedment

No heavy metals, no free silca

When glass is formed from sand the silca is becomes an amorphous silca, completely non hazardous.

Cuts Quickley

Glass is very sharp so it cuts though paint and other coatings very quick, but is no as heavy as most abrasives leaving you a beautiful white metal finish and profile, without damaging the substrate.

Glass comes in many sizes.

Dust is translucent which allows for increased visibility.