Earlier quoted context omitted.
Why should incentivizing the creation of economically unfeasible and unnecessary jobs be a goal? Such a system would be a huge mess of misaligned incentives.
False dichotomy A job is not either "feasible and necessary" or "unfeasible and unnecessary". Ultimately, the idea is that creating a job at a loss would be preferable to "giving money for free" because it could/would cost less, but not less importantly, it would be a potential for wealth creation. If, stupid example, somebody would be paid for running on a bike to produce electricity, that would create wealth by, sa…
The problem with such make-work is that you're paying people to do work which shouldn't be done. You're assuming that "staying at home watching TV" doesn't create any value—but it creates entertainment value for the consumer. If it didn't have any value, nobody would buy cable.
Let's say we have some totally trivial job. Say, generating electricity from running on a bike. The market wage for this would be $1.
In the status quo, we might assume that nobody would do that job. If nobody is willing to do that job, it means that their opportunity cost is greater than $1—ie. that even if they are unemployed, their non-market activity is worth more to them than $1/hr. Let's assume their non-market activity is worth $5/hr to them.
Now a government subsidy comes in and pays the employer $5/hr for everyone they employ. So the employer starts advertising bicycle jobs at $6/hr (in practice, they would keep some of the subsidy for themselves). Now the individual is willing to take the job at $6/hr.
Somewhat counterintuitively, this has destroyed value. In the status quo, we were paying nothing (no subsidy) and total value was $5/hr (the value the person gains from their leisure time). With a subsidy, we pay $5/hr and gain only $1/hr in total value (the benefit of the person riding the bike). This is obviously worse.
The only way that your system makes sense is if you treat leisure time as worthless. But that's clearly false: if leisure time was workless, everyone would work every possible hour and unemployed people would all be walking around the streets looking for pennies.