This is almost always the best and most efficient way you can help a cause. You donating infrastructure means donating them extra work - they'll need to integrate and keep track of it, as well as manage a relationship with you (in particular, a risk of problems with you or your service). Meanwhile, with extra cash, they can buy what they need and what integrates well, or pay the most effective specialists they need.
It's an universal principle. Cash is the best gift, if you're gifting to help. That's why e.g. Red Cross frowns at people donating stuff - it creates a huge logistical problem for them as well as depriving them of opportunity to boost the markets in the disaster-struck area. Or why it's better for you to donate money to your local homeless shelter rather than volunteer to work in it - if you work your job for extra hours instead, and donate that money, they'll hire workers better skilled for that task.