Economic growth helps states and ensures more goods for citizens. People spend more when there is economic growth. They can manage to have a decent life, without material shortages. Easier access to public goods and services has always been the basis for strong economic growth.
Politics is essential for the emergence of economic growth
Although you have stumbled across hypotheses in economics books according to which the economy and economic growth should not really be linked with politics, the reality is that without politics, one cannot hope for economic growth. It is politics that dictates exactly how economic growth happens and where its benefits are directed, toward which sectors.