VBA has been there for decades.
* It's rock-stable,
* Slowly changing (like C) so you don't need to learn all this fancy stuff each month and can focus on work (excel mostly used by non-developers if you didn't know)
* Everybody know it well already.
* Zillions lines of code exist right now.
* It's strongly typed (!!!).
Most of modern software already bloated, just look on electron apps and feel really sad thinking about browser running in my excel... What a shame.
I think it worth while to just make it compiled in webassembly so it will be possible to run it everywhere (main goal of current JS API).
I know that this will never happen in forencible future but anyway let it idea lay here for some time.