This is a debt issue, not a share issue. It could become dilution, but the conversion price hasn't been set. It's usually well above the current price. The company could repurchase the notes before the conversion price is met. And in any case, we now have the cash from the debt issue, without having sold any shares.
Cash is good when you want to buy companies and properties, fix depreciating capital, invest in new capital, expand operations...
And getting it at low interest is a good move when you know it will grow.
It can even be used to hedge against declines in the high market price of your product.