RPIs and organs could be fun! But...

1) that is not an organ, that is a simulator (an electronic organ playing samples through speakers)

2) a MIDI player (is it a Raspberry PI or not) is playing back files recorded og written by someone. A CD may do the same function acoustically, following this "logic".

3) being human, being a professional organist and being a fan of Raspberry PI, I think there are better ways to use a RPI than to deceive humanity with such contraptions.

4) if that "church" does not have an organ nor an organist, they should rather start with a piano and organize a bit of music school. Unless they don't what to have a ChatGPT pastor as well...