National Student Leadership Conference?

I want to major in biology and I’m interested in attending the NSLC biotech program. However, another program option for me is this volunteer abroad program in South America where you help build things, teach kids, etc. If I do this program, I would receive a President’s Service Award or something like that.
Which do you think would be more worth doing? The volunteer program that’s completely unrelated to my passion or the biotech National Student Leadership Conference program that is seen as “pay-to-play”?