I rank this as an essential hurricane survival tool.
If you live in any area with the possibility of the public water service being cut off by a natural disaster or just lack of electricty for your well pump thiese are excelent.
I live in a house with two full bathrooms so I have two bathtubs. When a hurricane is headed my way, instead of rushing out to buy bottles of water, I put this in one of my bathtubs and fill it with water.