Loose wavy hair refers to waves and curls. Compared to body waves, loose waves have tighter and smaller curls. It's not too tight and not too straight. Many women prefer loose curls. It looks more natural and fluffy, which is why many women choose to use it all year round.
The most important reason is the wrong size of the cap. If a lace wig is larger than your head and the hair on the sides doesn't fit your scalp, it will look huge.