"It doesn't matter" in this context doesn't mean "It has no value", it means "There is nothing at stake".
For example, I can afford to be a lousy jogger, because nothing bad is going to happen if I don't become faster. I couldn't afford to be a lousy engineer, because my family could end up homeless in a foreign country. That was the reality I lived at the beginning of my career.
For example, I can afford to be a lousy jogger, because nothing bad is going to happen if I don't become faster. I couldn't afford to be a lousy engineer, because my family could end up homeless in a foreign country. That was the reality I lived at the beginning of my career.