People I know all use different brands/items and it all seems to work.
I use the Shimano Road and have for 10 or 12 years. I selected this brand and style by walking into a bike store and going "Duh...I need some pedals."
My stoker uses Shimano mountain pedals and they work for her.
Another stoker uses Shimano Road like me, another used Look Keo.
I've used the Shimano mountain pedals on the gravel bike, and the difference is mainly that I have them mounted on different styles/types of shoes. But seems like the road pedals feel a bit more like what they ought to feel like, but that may be because I'm more used to them.
One confusing thing: People call the mountain pedals "SPD" but on the road pedals it actually says "SPD" right on the box, too.
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"be careful this rando stuff is addictive and dan's the 'pusher'."