The Tags in short describes your company and its products / services. The Search Engines have their own ways and policies which fetches these words searched by the user and displays the contents from the Tags. If the keywords is entered in the search box by the user are exactly same as the keywords updated in your Tags. The search engine will display your website at the first top 10 results.
I think any work done is never a waste of time. Work can be termed as waste if done at the wrong time...
