The "Sponsor a ____" is a marketing tactic, the end result is the same as setting up a regular monthly donation, it all goes into the same pot, unless it's marked for a specific cause or appeal.

However, there is a way to do this right. I donate to the Sheldrick Wildlife Trust, an elephant conservation region in Kenya. You can sponsor an orphan baby elephant, and they send you monthly updates on the elephant's growth, role in the herd (Bull, matriarch, mini-matriarch, etc), and you can follow their progress as they are rehabilitated and released into the wild.

If you just take the money and run, that sours people on giving monthly.