"You can only save from money taken from your household earnings (you won't save from loans), that is money which you would otherwise spend on consumption. Please try to explain how this can be any good for the economy in the long"
How can it not be good? Where do you think your consumption comes from, if not someone has produced them? How can you get it, without producing something of comparable value and trade? The savings in money and investments from prudent producers is the root of increased productivity, that benefits all.
Sorry, but I don't understand how what you say is related to what I am talking about. Yes, someone has produced what I consume, so if I decide not to consume (but prefer to save instead), there is overproduction (as simple as that). We are not talking here about producers' investments.