No it isn't - all it does is shift spending around. Money that could have been saved and spent later is being spent now in the hope that it'll create something of long term value that'll pay off more than invested. This is 'stimulation' in the same way that spiking yourself with coffee in the morning doesn't actually give you more energy in total, it just makes you feel more awake in the present at the expense of needing more recovery later.
Is Uber such a case? Maybe if it ends up with a long term, world wide monopoly on self driving taxi networks. But right now it's ultimately just a taxi firm that's burning vast sums of money giving people cheap rides. It's literally just throwing pensions and university donations onto the street without any plan for how to get that money back.
Yes! Too many people apply household economics to the state.
If anything has been proven since the GFC it's that Keynsian stimulus works (when it is supposed to be used not all the time, e.g. in a liquidity trap, i.e. now)
Into the pockets of drivers (although a portion of that comes from the pockets of existing taxi firms in opportunity cost and financing repayment).
So as a stimulant for the economy it is working. It is even trickle down economics in action !
It should also make incumbent taxi oligopolies up their game, so the customers ultimately win.
There will be losers. But that is the nature of the game.