At the advent of the internet, the purpose of meta keywords was to label your webpage with its key points so when someone searched for a topic that you wrote about, they'd find your page.
The meta keyword used to be really important to this process but isn't any longer. Instead, keyword research and content SEO are much more important tools to reach your audience.
Somehow, the topic seems to continually pop up in SEO circles: should we use meta keywords or not? The resounding response is no, get those out of here! There are better uses of your time that yield better return on investment (ROI).