Just because it's cool.
[HatTips2 dancohen, Open Culture, @hughmcguire, and MetaDeb]
Not to ruin the nice Coltrane vibe, but compare that to a saxophone playing robot. The video below shows the robot in action. The tone is awful, but it will give you some idea of what Coltrane is doing on the keys. Unfortunately it only shows the left-hand keys and we miss out on all the right-hand action, but you see can some of the high-note valves moving, which are operated by the right hand.
[Sax-playing robot image from Hosei University Takashima R&C Laboratory]
The keys are the easy part. The robot can get the notes, but isn't even close to making sounds like Coltrane.