Given this reference text about the Flex Computer System, why was it created?

The Flex Computer System was developed by Michael Foster and Ian Currie of Royal Signals and Radar Establishment in Malvern, England, during the late 1970s and 1980s. It used a tagged storage scheme to implement a capability architecture, and was designed for the safe and efficient implementation of strongly typed procedures.

It was designed for the safe and efficient implementation of strongly typed procedures.