Stainless steel is often considered to be a better material for jewelry than costume jewelry for several reasons:

1. Durability: Stainless steel is a highly durable and corrosion-resistant material, making it ideal for jewelry that will be worn daily. In contrast, costume jewelry is often made from inexpensive materials that can easily break or discolor over time.
2. Allergy-free: Stainless steel is a hypoallergenic material, meaning that it is unlikely to cause an allergic reaction in those with sensitive skin. Costume jewelry, on the other hand, may contain metals or other materials that can irritate the skin.
3. Low Maintenance: Stainless steel is easy to clean and maintain, and does not require any special care. Costume jewelry, on the other hand, may require special care, such as avoiding exposure to water, to prevent damage or discoloration.
4. Value: While stainless steel jewelry can be more expensive than costume jewelry, it is often considered a better investment due to its durability and long-lasting nature. Costume jewelry, on the other hand, is often considered to be disposable and is less valuable.

Overall, stainless steel is often considered to be a better material for jewelry than costume jewelry due to its durability, hypoallergenic properties, low maintenance, and value.

While there is nothing inherently wrong with purchasing costume jewelry, there are several reasons why one might choose not to waste money on it:

1. Short lifespan: Costume jewelry is often made from inexpensive materials that can easily break or discolor over time, making it less durable and less likely to last for a long period of time.
2. Poor Quality: Costume jewelry is often mass-produced and made with less attention to detail and craftsmanship, making it less likely to have the same level of quality as fine jewelry.
3. Lack of value: Costume jewelry is typically not considered to have any intrinsic value, as it is not made from precious metals or gems. This means that it is less likely to hold its value over time, or to be passed down as a family heirloom.
4. Allergic reactions: Some people may experience an allergic reaction to the materials used in costume jewelry, such as metals or other alloys, which can cause skin irritation or other symptoms.
5. Poor resale value: In contrast to fine jewelry, costume jewelry often has very little resale value, and is not considered to be a good investment.

Overall, while costume jewelry can be a fun and affordable accessory, it may not be the best choice for those who are looking for jewelry that will last for a long time, have a high quality, or hold its value over time.