It's a common assumption, but hardshell helmets aren't necessarily safer—they're just built differently. A hardshell helmet has a separate tough outer shell (usually ABS plastic) that's glued or taped to the inner foam liner. That solid feel is great for durability against everyday bumps, drops, and dings, not crash performance.
Hardshell construction really shines for BMX, skate-style riding, and everyday commuting where your helmet takes a lot of casual abuse. They tend to be more affordable too. The trade-off is weight—hardshell helmets are noticeably heavier than in-mold designs.
One thing to keep in mind: in a severe crash, the outer shell can separate from the foam liner, which isn't ideal for energy management. For road cycling or mountain biking where weight and impact performance matter more, in-mold construction is usually the better pick. But if you want a helmet that holds up to daily wear and tear, hardshell is a solid choice.