Because they need to park Capital somewhere that gives a return, even if it's a small one.
It's not a bet that interest will stay low as much as I bet that they as a company will be around in 10 years to see the returns. It's a guaranteed profit if they make it to the finish line.
Of course it's a bet that interest rates will stay low, as subsequent events have amply demonstrated.
Managing to hang on until maturity doesn't magically make it turn into a profit, when you consider the time value of money. The bonds are worth so little today precisely because they're only returning the original amount at maturity, plus 200 year low interest.
