The difference between convertible debt and non-convertible debt is

convertible debt is not affected by interest rate changes, while non-convertible debt is.

convertible debt is not considered a liability since it can be exchanged for stock, while non-convertible debt is.

convertible debt can be converted into stock at any point in time, while non-convertible debt can not.

convertible debt can come with downside protection, while non-convertible debt does not.