In a Decathlon store in Paris, I found inserts I could clip into my SPD pedals to turn one side of them into platforms. I bought them and rode the rest of my tour in Europe with them. I really like them!!
They allow me to wear regular shoes if I want, or my cycling shoes ... and what I especially found nice was that in heavy traffic in cities like Paris, London, and Strasbourg, I could ride with my left foot clipped in, and my right foot on the platform ready to drop at any moment if someone stepped out in front of me, or a car suddenly turned in front of me, or whatever.
So in some of my touring photos, when I get around to posting them, you'll see me in sandals, instead of my usual cycling shoes.
It might be an option for some of you who like your clipless pedals, but also want the freedom to just hop on your bicycle and ride with whatever footwear you have on.