I support a prorated version, but the common criticism is that it's more open to fraud and harder to implement. I still think a prorated[1], guaranteed minimum income is better than a basic income.
1) something like reducing that payment by $0.50 per $1 earned as an example.
It's just an unnecessary wrinkle. Taxing earned income is the same as doing what you propose, but incurs higher coordination costs. Also, using your example, it's regressive taxation unless the base rate is higher than 50%.
I don't think paying everyone is a good idea and will encourage inflation to make the program useless. I'm fine with regressive when talking money given to you.
1) something like reducing that payment by $0.50 per $1 earned as an example.