Excel is the same way. Every big number-crunching outfit knows that you mustn't build big important things out of Excel, even if they had to learn that the hard way. Yet, inevitably, somebody in those outfits is doing something in Excel because it was fast and they knew how. One day their pet project will get scaled up and it'll fall to pieces because it's built out of Excel when it really shouldn't be.
Excel has lots of the same frustrating properties. For example reluctance to announce failure (always better to eat reference errors, invalid inputs, etc. and spit out a superficially plausible answer anyway). But backwards compatibility is vital, so most of the problems can never be fixed, or if they are, they'll cause even more unexpected pain and misery for existing users.