Why is oil applied in layers to the sofa armrest solid wood instead of urethane coating?

It is the difference between a film that covers the exterior and oil that penetrates into the inside.

For the armrests of BY HEYDEY's Concord Sofa, red oak solid wood is used, and it is finished by applying eco-friendly oil multiple times in layers instead of urethane coating^[1]. Generally, urethane coating is a processing method that puts a transparent and hard synthetic film over the wood exterior to prevent stains and scratches. On the other hand, oil finishing is a method where oil components penetrate into the wood grain to preserve the breathability and natural texture of the solid wood itself.

hmmm, considering the nature of sofa armrests where hands rest for a long time, it is closer to a practical finishing choice that leaves the original touch of wood on the fingertips instead of a cold coating film.