IMHO, this is ripe for abuse.
First, it eliminates what's left of the stigma of being on government assistance
Second, it eliminates motivation. Why work when you are guaranteed an income?
Third, it encourages illegal income. "You mean I can deal drugs AND get a government check too?"
Fourth, the controls on current government assistance programs are really poor, but at least they are there. Boozers would have NO restrictions on buying alcohol with their government income
Fifth, this only encourages big government. Who are people on a minimum income going to vote for? Those who will raise the minimum amount, of course.
Addressing your good points:
1 - So much of government assistance is online these days which has damped down the stigma
2- Yeah and why work when you get SSDI, welfare food stamps, etc? Same thing really.
3 - see 2
4 - money is fungible, see 2
5 - again, see 2.
We already have welfare. I think guaranteed income, as long as it's in lieu of welfare, SSDI, food stamps, would be better for a variety of reasons.
Don't get me wrong, I'd get rid of welfare et al. if I could (although SSDI might still be necessary). Politically speaking though, it just ain't gonna happen. Another conservative pipe dream. We have to play ball with pea brained fools called liberals.