"Powerwall" is just a big battery.
Yes... plus some electronics, like a rectifier, an inverter and control circuitry.
It might help compensate for the irregularities of solar and wind power.
Yes... that's partly what is was conceived to do. It also can compensate for the irregularities in demand.
But it only makes sense to use batteries for that after we have moved to much more renewables.
For storage of solar and wind power, this is a complex matter, and the short answer is "it depends". For demand management, it makes sense now.
It is much more efficient to store the power in the water magazines of existing hydro plants.
It is desirable to use hydro plants (where they exist) as swing producers. Pumped storage is not quite as energy-efficient as battery storage (roughly 75% for pumped vs 85% for Li batteries), though it can be cost-effective, in places where large, elevated reservoirs already exist.
But all this is besides the point, which is: There are proposals to "solve" global warming, which are implementable now, with today's technology, which furthermore have side effects which are on balance positive (like clean air in the cities).
Gets a big loan from Russia that prevents an economic collapse (20% likely)
I'll give 10:1 odds against this happening. Russia has its own economic problems now with the drop in the price of oil and Ukrainian conflict, and other issues... China might be more likely, though IMO both Russia and China are a scare ploy by the Greeks.
A somewhat likely possibility is: Greece leaves the EU, triggering an economic collapse, possibly followed by a political collapse. Then spends many, many years trying to sort out itself and wishing it had stayed.
In the "proof" presented, the series 1-1+1... is "shown" to equal to 1/2 by a particular choice of interleaving of the values in the series. But with other methods of interleaving, the sum can be made to "equal" 0, 1 1/3 or indeed AFAICT any rational number between 0 and 1.
So... why is the particular interleaving that gives 1/2 as the answer "correct"?