Of course it’s a waste of time. It’s political theater, and would accomplish nothing of any significance, besides giving every House R the ability to go back home and say “I voted for impeachment”.
Obviously, you have a very cynical outlook on politics and life. You don't seem to get or respect other people's outlook on this. We don't do something only when you are guaranteed to "win" or "accomplish something of significance." We do something because it is the right thing to do. And we give it our all, expecting nothing in return but the satisfaction that we did the right and correct thing. We are just expecting our representatives to act in a like manner.
If you don't understand this, perhaps you need to do some reflection on your political philosophy and outlook on life in general. People with attitudes like yours will never "win" or accomplish anything of significance.