The real-sector-economy is basically production of both agricultuiral and industrial goods, their exchange/marketing, other essential services like education, health, etc., as well as research, art, philosophy, etc., that satisfy various needs of human beings.
Banks are an institution that collects money from the clients to serve their need of safeguarding that for them, and provides there-with the finance for the real-sector-economy.
Impetus implies that Banks play the role of spuring people/institutions/industries/etc. to operate/perform/produce/exchange/etc. the goods or services or other things of the real-sector-economy.