Chicken or the egg? It seems equally intuitive that investment drives the economy. Investment gives companies capital, capital to spend on employees and services or products from other companies (which in turn spend it on employees or other companies). In this way, money makes it way into the pockets of consumers who then spend it on products and services, and the endless cycle of economic activity continues.

But I'm not an economist and am somewhat skeptical of macro-economics in general, which seems a bit like reading tea leaves.

Even if you if you don't buy into supply side economics, I think "Money doesn't do anyone but the holder any good sitting in an offshore account" is somewhat misleading. Savers and investors, through loans and capital, certainly help someone.