Why is Python so popular despite being slow?

I came across an amazing answer for this by Alec Cawley on Quora.

What does it matter if a program runs in 100 msec instead of 1 msec, if only run it a hundred times? If it takes me 10 minutes to develop instead of 60 minutes, I have gained 3000 seconds and lost 10. Isn’t that the right way round?

The only reason for computers is to help us. By running an easy-to-write language, they help us. You need to prove the necessity for a hard-to-write language. There are such proofs – many applications really need performance.  But for the many that do not, Python is an excellent language.

Originally Answered: Why is Python in demand when it is slower than other languages?