> because we risk contaminating Mars with organic stuff coming from the Earth.

What is the alternative, not go to Mars?

"Useless" and "counter-productive" are value judgements, not objective conclusions.

My opinion is that landing humans on Mars could be the start of a new age of exploration, which would massively benefit humanity. And the risk of contamination is worth the potential reward.

That's just my opinion, of course, but it happens to be NASA's opinion as well.

Landing on Mars is the artifact of all of the innovation required to get to Mars. We benefit from the innovations, not the landing per se.

Memory foam, smart phone cameras, tech miniaturization in general, GPS, baby formula, cordless tools... just a tiny sliver of things we use daily that are directly attributable to the pursuit of space travel.

It is far from useless

Was the Wright brothers’ first flight useless, or did it teach us lessons that lead to the Concorde and 777?

Was the first automobile so slow and clunky it was useless, or did it lead to the F1 cars of today?

Was Alan Touring’s computer so slow it was useless, or did it lead to this comment being typed on a device that is many orders of magnitude faster and smaller?

Going to Mars will teach us a lot. In the future when we go further it will be useful in ways we can’t imagine today.