To look and feel nice is the short answer.
Many men – although a lot of men are becoming more woke and understanding that not everything a woman does is designed with pleasing a man in mind – think that pretty clothes, make up, lingerie and exciting underwear is worn for their delectation. This is not true.
Women are raised – from birth, practically – to look pretty, to be nice, and to not make waves. This means that for generations of women, the way they look dictates the way they feel and their feeling of worth and self-esteem. This means that there are women who will never leave the house without a full face of make up, and there are those who will not even spend the day inside, by themselves without dressing ‘properly’ and looking presentable. Fortunately, social mores are changing and women are less likely to behave in this unnecessarily decorous manner, but it will take time – and several generations – before society stops judging women primarily on their looks. And for women to understand just how entrenched this trend is and how it permeates our lives from birth to death and everything in between.
So women wear lingerie because it feels good and looks good, and it makes them feel lovable, worthy and deserving of whatever it is they are looking for: love, respect, desire etc. They do not wear lingerie to ‘attract’ a man, to seduce a stranger, or any of the other fairy tales that circulate about women who dress attractively. The only exception to the seduction point is when a couple are in a happy, committed and intimate relationship, and she feels confident enough to indulge one of his fantasies (for example) by dressing up in slutty and inviting lingerie. This is perhaps the only time that a woman will ever dress up by wearing sheer lacy clothing for the sole purpose of inviting the amorous advances of a man!