There are many reasons why someone might choose to use a packer. Here are a few:

1. Gender expression: Some people use a packer to create a more masculine appearance or to help them feel more comfortable and confident in their gender identity. For trans men or gender non-conforming individuals, a packer can be an important part of expressing their gender identity to the world.
2. Dysphoria relief: For some people, not having a penis can cause gender dysphoria, which can be alleviated by using a packer. A packer can help create a more realistic appearance and may help reduce feelings of dysphoria.
3. Sexual pleasure: Some packers are designed for sexual use, and can help individuals who have undergone genital surgery or who may not have a natural penis experience sexual pleasure in a more realistic way.
4. Comfort: Some people find that using a packer is simply more comfortable and natural for them, and can help them feel more at ease in their body.

Ultimately, the decision to use a packer is a personal one, and the benefits will vary from person to person. However, for many people, using a packer can be an important part of their gender expression and overall sense of well-being.