[lambertsimnel]

You're substantially right, of course, but to play devil's advocate:

1) the negative real central bank interest rates are a recent anomaly in my country, and above-inflation deposit interest was easy to find before that

2) mortgage lending should indirectly generate meaningful economic activity, in the form of building construction and maintenance

3) buying stocks on the secondary market also only indirectly generates meaningful economic activity - all it does directly is take stocks out of the seller's hands, replacing it with cash - presumably, this causes a chain of trades that lead to the primary market (or possibly to a mortgage)