Yes, they are good. Yes, they are no good. Both can be correct, but since you don't tell us much, we cannot tell you much.
It's just to know If it is good or not to index in the search engine the url of the web that contains / tag /
Tags with title and description attributes or other tags organizing the content, can have a relative impact on rankings if done right.
I just love how so many people come on DP expecting us to be God and read their minds. Give us SOMETHING to work with! We are NOT God, so CANNOT read your mind!
I didn't reply initially because I had no idea what an "index tag" was, but was curious to find out. @Wey are you referring to urls that have keywords in them?
tags are good for the readers. I like tagged posts when I am reading on a site. It drives me nuts when I am on a local news site and they don't tag the articles. tags can create a mess in the index, but google is now learning to not list the same page 20 times , you know, categories, tags, links, etc. The indexing will be much neater in the future. So, when it comes to tags, think about your reader.
You can make a thread deletion request via the report button, I know that you know how to do that. This thread doesn't violate the forum's rules so your request will be rejected. Why have you ignored the requests for clarification of the topic?
You can unsubscribe from the thread so you will not get notified every time somebody posts in it. And, I think you can have your thread closed if it has served its purpose. ETA. Sorry for giving you an answer to your question, I did not see your request to delete your question.