It's not medical advice nor did I invent it - it's just one of the regimes for PrEP recommended by the WHO. I know people on PrEP who were unaware of this regime, since the default consideration is the daily dose. Like all things, it's something to discuss with your physician.
As the WHO notes, the event-driven regime isn't generally recommended for adolescents who might have issues with compliance, or cis & trans women.
https://www.who.int/hiv/pub/prep/211/en/