To some extent, your tags are not the only tags because everything you write in the video description is findable at least by Google and other search engines. Google has found my Steem posts by finding random words I write, I wrote, in my posts, in the body, and not in the tags alone. In theory, to say the least, the Dtube search engine should be able to find anything that Google can find or maybe someday it will. At the moment, the Google search engine seems to be better, more powerful and accurate or whatever.
And you have to wait 8 days or long enough before Google or Steem or Dtube or other search engines can find your posts or videos from any of the words in the titles, the descriptions, content, and not just fdrom the tags alone.
But I do agree that better tags, real tags, with multiple words, and more, helps.