Great question:
Simple answer - To prime the economic pump via Kynseism economic theory.
It worked well coming off the home mortgage credit default debacle.
Trump needed to switch models when he came in and did.
I think he went too far with removing environmental regulations and corp tax breaks.
BUT, he's gotten some results in the process.
Question for you : Why can't BOTH sides just admit both men have done well with our economy.
The numbers show that overall. Saying Obama or Trump was/is Herbert Hoover is crazy.
The economy under Obama would have grown much faster if nothing were done. Economy's do not grow by regulating the shit out literally almost all industries, driving corporations and jobs out of the country, misappropriating funds, printing money to create a false economy, Obamacare, Obamacare mandates, killing job-creating projects and taxing the shit out of everything and everyone.