Cookies greaseproof paper bags are popular for several reasons:

1. **Moisture Resistance**: Greaseproof paper bags are specially treated to resist moisture and grease. This helps maintain the freshness and quality of cookies by preventing them from becoming soggy or oily.

2. **Aesthetic Appeal**: These bags often have a rustic, homemade look that appeals to consumers. They can be customized with logos, designs, or labels, enhancing the branding and presentation of the cookies.

3. **Eco-Friendliness**: Many greaseproof paper bags are made from biodegradable or recyclable materials, making them an environmentally friendly packaging option compared to plastic.

4. **Convenience**: They are easy to use and can be sealed with a simple sticker, ribbon, or tie, making them convenient for both bakers and consumers.

5. **Versatility**: These bags come in various sizes and can be used for different types of baked goods, not just cookies. This versatility adds to their appeal.

6. **Cost-Effective**: Compared to more rigid packaging options, greaseproof paper bags can be a more economical choice for small businesses and home bakers.

These factors combined make greaseproof paper bags a popular choice for packaging cookies and other baked goods.