Dividend coverage tells you whether a company can keep paying its dividend out of cash flow. A coverage of 1.0 means every dollar of free cash flow goes straight out as dividends, leaving no room for a bad year. A coverage of 2 times is comfortable. Below 1 means the dividend is being paid with borrowed money or by selling assets, which cannot go on forever.
For a company that pays no dividend, this ratio does not apply. Many quality businesses, such as Berkshire, Google, and Amazon, choose to pay nothing and instead reinvest all their profits at high returns. That is not a bad thing.