Are linen wrinkles a defect?
No - wrinkling is intrinsic to flax fiber. It is the accepted texture of linen, and only sharp creases at seams need pressing.
Flax fibers have low elasticity: bend them and they stay bent, which is why linen creases the moment you sit down. This is not poor quality; the finest Italian linen wrinkles just as readily as the cheap kind. What distinguishes good linen is even slubbing (the subtle thick-thin texture), a tight weave, and softening with each wash rather than weakening. If you want the linen look with fewer creases, choose a linen-cotton or linen-viscose blend - you lose some coolness and gain stability. Never buy linen expecting it to behave like poplin; buy it because rumpled is the aesthetic.