1. Security: FTP itself is not the most secure protocol, as credentials are sent in plain text unless FTP over SSL (FTPS) or SSH File Transfer Protocol (SFTP) is used. However, with proper configuration (such as using FTPS or SFTP), it can be made more secure.

2. Scalability: FTP servers can handle a large number of file uploads and downloads, and they can be scaled horizontally to handle increased load.

3. Management: Managing files on an FTP server might require additional tools or software. However, once set up, it can provide a centralized location for file management.

4. Integration: Some systems or legacy applications might require FTP for file transfer. In such cases, integrating with an existing FTP server could be beneficial.

5. Access Control: FTP servers typically provide fine-grained access control, allowing you to control who can upload, download, or delete files.

File System Storage in ASP.NET Core:

1. Security: Storing files directly in the file system can be secure if proper permissions are set on the directories. However, there might be risks associated with direct access to the file system, such as potential vulnerabilities if permissions are misconfigured.

2. Scalability: Direct file system storage can scale to some extent by adding more storage drives or using network-attached storage (NAS). However, scaling horizontally might require additional complexity.

3. Management: Managing files directly in the file system might be simpler and more straightforward compared to managing them on an FTP server. Tools and libraries for file system operations are readily available in ASP.NET Core.

4. Performance: Accessing files directly from the file system might be faster than going through a network protocol like FTP, especially if the application and file storage are on the same server.

5. Integration: If your application primarily deals with file storage and retrieval, storing files directly in the file system might simplify integration and reduce overhead.

In summary, whether file upload to an FTP server is better than storing files directly in the file system in ASP.NET Core depends on your specific requirements and constraints