Synthetic leather shells are a great choice if you prioritize a soft, broken-in feel right out of the box. They're lighter than molded plastic (TPU) shells and flex more naturally, which is why you'll find them mostly on freestyle and soft-flex boots. If you spend your days hitting rails, jibbing, or just cruising relaxed turns, that softer flex can feel more comfortable and forgiving.
The trade-off is that synthetic leather may stretch over time and can feel slightly different in very cold temperatures compared to TPU shells. They also tend to break in faster, which means the flex you feel on day one will soften up after a season or two. Look for models with internal reinforcement panels in high-wear areas—they help maintain structure where you need it most.
If you're an aggressive all-mountain rider or charge hard in variable conditions, you might prefer the consistent flex and durability of a TPU shell. But for park riders and casual cruisers who want comfort and a softer ride, synthetic leather is a solid pick.