It's no secret that learning to play the thumb piano may very well be the easiest instrument to learn to play. Unlike a traditional piano, the most common 17 key kalimba only has 17 keys (obviously), compared to 88 keys on a common piano. This fact alone makes learning the kalimba significantly easier, and removes playing any complex chords from the learning process.
Simple instruments are an extremely useful tool to have, especially when dealing with children. If a child possesses even the slightest desire to learn an instrument, they will be able to play something enjoyable in a matter of minutes with a kalimba. This could blossom a life long love for instruments and music in general, which is what makes the kalimba so amazing.
In my musical experiences, I only learned to play the recorder and the trumpet. I learned to play the recorder in grade school as a part of the band, which every student was required to do. To be quite honest, I believe learning to play the kalimba was even easier than the recorder! Maybe I need to show my old grade school band teacher what a BoldMusik kalimba is... :)