Compared with traditional manual weighing and unattended weighing system, which one is more cost-effective?

It depends on your on-site usage. Normally, it should be left unattended to save money. If you weigh less often and there are usually people who can handle the weighing part-time, then manual labor is fine.

The most common unattended solution is to add a camera, infrared, speaker and software. It doesn’t cost much, and if you are specifically arranging for someone to do the weighing, it is recommended to install one.