I don't agree with the vote to close the question "Why is the MKS unit of time the same as the CGS unit?". The question is, when Giorgi proposed to replace the CGS system, could he alternatively have chosen to replace the unit of time instead of the unit of mass. The answer is "no", because Giorgi aimed for coherence with the practical units ampere, volt and joule. This answer has been accepted by the OP.
User FGSUZ voted for closing the question because it might belong to HSM. But we are using SI today, so it is a question about today (why is the kilogram the SI base unit of mass). Kyle Kanos diverts from the question, which is about the replacement of CGS by MKS, by mentioning natural units. Other voters do not explain their vote. Some users incorrectly seem to imply the change from CGS to MKSA was arbitrary.