Whether someone needs a cycling shoe or not probably depends on the type of pedal, mileage, and maybe how well a person’s foot can absorb abuse.
A quill pedal is basically a blade that puts all the pressure, at least the back, at a single point of the shoe. When quill pedals were about the only option, companies like Avocet offered a semi-rigid walkable touring shoe that spread a lot of that pressure over a larger area. For most road riding, it would probably still one of the better options if available today; though the toe box was a little small.
I ride platforms on my mtb’s with hiking shoes from Big 5. They work fine with the larger contact area of a platform. It is also a good option if something causes you to get off the bike for some reason. Probably good for a couple hours of riding.
Even still, for riding any sort of distance, a supported sole is nice. Even a sole with some rigidity is a plus. It doesn’t have to be one where you need to waddle to walk around.
I think, not sure, there are a few companies that make walkable cycling shoes that can be used with quill or platform pedals. That would be my choice for any distances. I do use a semi-rigid touring shoe with my road bike, as I think there are foot support benefits without the lack of walking issues with totally rigid cycling shoes.
John