However if you spend the money then there is a multiplier (the shop where you spend the money uses some of it to pay an employee, who then uses it to buy their own gadget etc.) but it is much smaller.
Or the money is eventually paid to a corporation where it adds to its profit, and may be snarfed up by a shareholder who - gives it to a hedge fund to invest.
The point is more that conventional wisdom is nonsense, because the model used to define concepts like 'saving' and 'spending' is too old and decreptic to tell you anything useful.
Savings used to mean money under a mattress or big piles of gold. The gold wasn't very mobile, so it tended to stay where it was.
Now 'savings' can be multiply leveraged through recursive multipliers, and 'spending' is as likely to be done with borrowed money - secured agains someone's savings or other liquidity, at least in theory, if not so much in practice.
What it comes down to is the fact that the markets own money. It used to be the case that money ownership was at least partly distributed.
Now individuals pay:
A 'reform' tax - lower wages because markets want higher returns
Traditional usury taxes - money borrowed at extortionate rates on credit cards
A disinvestment tax - savings are poorly rewarded because returns on investment and liquidity are trapped higher up the food chain
'Saving' is irrelevant as a concept when the markets have become a black hole which sucks in liquidity and recirculates it inside a market-made event horizon.