These are fairly sturdy and designed just as it says and depicts in the listing. I often have brainstorms, write out thoughts, etc. and didn't want to use up paper to throw it away all the time or risk writing things in the wrong notebook as I so often do. These allow me to write out my ideas and either erase them or transfer them to the appropriate notebook/device later. I can have them all over the house or even take one on the go.
CAVEAT - the marker residue lingers more than on normal metal boards. Be sure to clean regularly with glass cleaner, etc. to prevent permanent smudges/staining.