From what I've read in the past, It's intermediated (sort of?) like Kiva. Everyone an end-user sees is already promised funding by Watsi. The "pick a person" is sort of a feel-good, and perhaps a way for Watsi to refine their process for choosing "fundable" candidates.

To me, the photos are problematic: They increase funding, no doubt, but for all the wrong reasons. Donors shouldn't care about patient photos, except as part of some general evidence to reassure users that Watsi is not running or becoming the victim of a scam.