The debt/equity ratio is a balance sheet measure, but doesn't say anything about how much money a company is making, which is an Income Statement question. The Times Interest Earned ratio is important because it addresses the Income Statement.
Say that a company has $10 million of debt at a 10% annual interest rate. Even if the company had $10 million of equity, or a debt/equity ratio of 1, which is generally looked at as favorable - but the company only earns $500,000 per year, then it wouldn't be making enough money to cover its annual interest cost.
So, in your example, if two companies have similar balance sheet profiles (debt ratios, etc) but one earns 5 times its interest cost and the other only earns 1 or 2x interest, then the one that earns more is in a better financial position.
Hope this helps.