The main difference between the two types of accounts is that a Personal account is owned and managed by the adult. A child owns their account, but it's managed by the adult on their behalf until they reach 18.
Any money that comes into a Kids account, and any investments made, belong to the child. Money put in and put towards investments in an adult account are owned by the adult.
As an owner of a Personal account, you’re taxed at your prescribed investor rate (PIR). For Kids accounts they’re taxed at the child’s PIR.