Pebbles and sand might be safer to hold if they are less volatile than BTC. A company like Paypal needs stability, not a directional bet on an asset.
Unproductive investments are basically the constant increase in stock and housing prices over the last decade. You're not buying those to make more money, there simply is no other place for the money to go. The only way the savings rate can be reduced domestically is through unemployment or underemployment. Unemployed people don't earn money but they still have to spend, which reduces savings.
It's a truly hopeless situation for the humans living the USA. But hey, at least the dollar is still "good".
Oh right, presidents are taking on debt to cancel the savings glut that was forced upon them. That's a bad thing.