I'm referring to established charitable organizations that run many such trips a year, all over the world. Lots of staff are needed. Not just surgeons, but scrub techs ( see above) anesthesiologists, nurses, translators, and people to do a lot of the support work: paperwork, keeping track of supplies, etc. Just as in a hospital, there is far more support staff needed than physicians . There's plenty of work for un-trained staff, otherwise they wouldn't be brought along. Most will pay their own transportation and lodging costs.
So, the work is charitable, and needs to be done. As to which is more valuable, a well, or the cleft lip repairs, or cataract removal, that's debatable and probably unknowable.
The cynic in me believes that all charity is ultimately selfish. The donor prefers the benefits they get from giving the money or time, in the form of virtue gained, public accolades, or conscience assuaged, to the utility of keeping the money. That's not to say that the recipients don't benefit, or that donors shouldn't give, but whether the reason is guilt, admission to med school, broadening one's horizons, or trying to get into heaven, it's all done for a reason.
