They offer no support
Flat flip flops offer the feet no support and commonly have loose straps. These design flaws often leads to an abnormal walking pattern and the transfer unwanted stress and strain to the musculoskeletal system which may lead to injury.
A lack of support causes the foot to pronate like below:

Foot pronation doesn’t just affect your feet—it can place stress on your knees, hips, and back, as shown below.

Traditional flip flops have loose straps
Most traditional flip flops are designed with loose straps. This causes the toes to claw down in an effort to grip the footwear and keep it on the foot.
Normally, when you walk, your toes should point slightly upward before your foot strikes the ground. This upward motion activates the arch of the foot, helping to lock the foot in place and provide protection and support as your body weight makes contact with the ground.
However, when the toes claw down—as they do in loose flip flops—the arch cannot activate properly. Without this natural bracing, the feet are left unprotected, more easily fatigued, and vulnerable to stress or injury.
Auras Flip Flops are designed with a snug strap that reduces toe clawing, allowing you to walk more naturally. This ensures your arches activate as intended, so your feet can perform their protective, supportive function with every step.
'Traditional' flip flops with loose straps

Auras Flip Flops have snug straps
