Nylon or composite soles are a solid choice for most recreational riders, commuters, and anyone just getting into cycling. They offer decent stiffness for efficient power transfer, and you'll only notice some flex under really hard sprinting efforts. For casual rides and everyday pedaling, that slight flex is barely noticeable.
The big advantage of nylon is comfort and value. These soles are more forgiving on your feet during longer rides, and they're much more walkable than stiff carbon plates. They also cost significantly less, making them a smart entry point if you're not racing.
If you're doing competitive road racing or high-intensity efforts where every watt counts, carbon will give you a stiffer, more responsive platform. But for most riders who balance cycling with walking breaks and don't need race-level efficiency, nylon soles deliver plenty of performance at a friendlier price.