If find the idea of a cycling specific flat shoe a bit odd tbh. the whole grip thing people go on about here is overrated, you don't need to be stuck to the peddles.
More to it than grip. I've tried a few different types of shoe over the years (been riding about 15 years, never on SPDs), from approach shoes to hill running shoes to skate shoes. I've had skate shoes that turned into sponges, approach shoes that provide no pedal feel and hill running shoes that were the perfect solution for 3 months until the soles were shredded and tore through. Currently running some Vibram soled Merrels - great for the weather, bloody useless on the pedals.
Really am fed up of having to settle for compromise in such a basic area as winter footwear, while simultaneously free to choose between a million different shock damper settings and tyre compound/tread pattern/size combinations. I'd trade all the fancy axle paths in the world for just one decent pair of riding shoes.
It isn't odd. It's a glaring gap in the market. Hill running shoes with pedal friendly soles is all I've been waiting for, personally. Something that copes with bad weather in the Peak. In a world of 50 different headset standards, a new riding sub genre appearing every time I blink and niches being invented and turned mainstream on an almost weekly basis, it's hard to see how flat pedal cross country riders have been overlooked. Not everybody out on the trails wants to clip in.