It does takes significant investment to get to this point though. SCB have been building APIs and components in Haskell for 8 years. We can now glue these part

It does takes significant investment to get to this point though. SCB have been building APIs and components in Haskell for 8 years. We can now glue these parts together very easily and can be confident it will work, thanks to strong types. With less disciplined languages and/or teams, 8 years of development can yield a codebase that most will want to throw away and start again.