What YAML is
YAML uses indentation instead of brackets. It is a superset of JSON, supports comments, and is meant to be edited by hand.
Kubernetes manifests, CI pipelines, Ansible playbooks and most modern config files.
What INI is
INI is the oldest configuration format still in daily use: named sections, then key equals value lines.
Windows software, PHP, Git and a long tail of tools that never moved on.
What changes when you convert YAML to INI
A YAML list of maps reads as rows and columns directly. Anchors and aliases are resolved before the table is built, so a repeated block arrives expanded rather than as a reference.
Each row becomes a section named after its first column, with one key per remaining column.
What carries over from YAML to INI
YAML records 4 things about a table that INI has no way to hold.
YAML distinguishes a number from the text of a number; INI does not, so every value arrives as text and has to be re-parsed by whatever reads it next.
An empty cell and a missing one are the same thing in INI, so a null and an empty string in the YAML both come out blank and can no longer be told apart.
YAML can hold a value that is itself a list or an object. INI has only flat cells, so nested values are flattened into one cell rather than being spread across columns.
A line break inside a cell ends the row in INI, so line breaks are replaced rather than carried through.
The identifier 007 comes out of the INI as 007. Reading it as a number would have made it 7, and an id that changes value is worse than one that stays text.
The role "Analyst, data" survives with its comma, in one cell rather than split across two. That is the first thing to check in any converted table, and the usual place a INI file goes wrong.
The quotes around Jonah "Jo" Pryce are left as a plain quote character in the INI.