Why do companies issue convertible bonds?

Companies issue convertible bonds for at least four reasons:
(1) to minimize the interest rate on their debt since the conversion feature forms part of the lenders’ value,
(2) to raise funds in a poor stock market that will eventually become equity at a much better share price,
(3) to create financial leverage for a period of time which then disappears upon the bonds’ conversion, and
(4) to use and then automatically free up debt capacity.