The TSA is a jobs program, and one that was easily sold to a part of the electorate that typically resists jobs programs. Granted, I’d rather just cut people a cheque and skip the theatre.
Money has to seem scarce and earning it needs to be by doing things we consider work. Without both, most people would likely realize that our monetary system is one big game rigged against them.
Writing everyone a check just increases prices and racks up more federal debt.
The real kicker is that we simply can't test it. There have been studies trying to do a real world test, but the data is useless because they can only test a small bubble of people getting free cash in the middle of our existing system where no one else gets that same money.
That's still a failure in my opinion. If the government has to create jobs for the sole purpose of employing people then our economy failed to create enough demand for real jobs and people failed to create demand for their own labor independently.