Why working on travelings and spend money for it some will ask ?
Well, there  are some reasons

First it is a great feeling  to work for a good cause and do completely different things than in your normal life
(like planting Banana trees)

You meet exicting humans throughout the whole world and find new friends

You experience adventures  a normal tourist seldom experiences like a picknick with cambodian rangers in the rainforest

and yes  –  I will continue this list