not sure about Michelin keys but from my experience the "guide" has declined severely after it became "pay to win" in the last decade where local governments pay Michelin to bring their ratings for tourism promotion.
and even in its original european market, they say one star in Italy is worth two in France. i thought the phenomena was not good for the Japan and New York guides (the guide overrates japan especially) but since then they've doled out stars in new markets like candy.