The Namibia study is interesting, but it's essentially attacking a different problem from the one Kidisha aims to address (lack of access to relatively high sums by local standards to do specific things)

It's also unfortunately too short term and micro-scale to really address the main criticisms which are (i) prices of basic goods in short supply and ground rents will rise to the point very poor people are often not better off, and sometimes worse off (ii) trying to set the basic income sufficiently high to allow subsistence (which the Namibian study didn't) would cause massive economic instability even if it could effectively be funded (iii) without massive and relatively expensive administrative oversight, most of the money will be siphoned off by the corrupt in underdeveloped countries and regions and (iv) if you make payments for children you encourage even more excessive population growth and if you don't, families still suffer.