They obviously have determined they have sufficient cash for...

They obviously have determined they have sufficient cash for that, and therefore any extra cash above what they need is inefficiently used by sitting in a bank account doing nothing. In that case, the most efficient use of cash is to return to shareholders. It is textbook capital management

They have also determined that the share price is currently well below the intrinsic value, and that in the future when they may eventually need to raise more capital they can do so at a higher price. They are basically buying low and selling high in the future when they eventually need capital, which again is great capital management