And considering the origin of the name Jupyter (Ju:Julia, pyt:Python, er:R) I really thought that Pluto, starting with a P, would be for Python.
P:Python, lu:Lua, to:Go as prounounced by a baby - given Pluto's size...
In many cases, Pluto's execution model would be prohibitively obscure (despite being 'pure'). E.g., at work I quite often have 100gb-ram Jupyter notebook kernels, where running one extra command or running commands in a wrong order would simply cause the box to crash.