One of the examples you gave, Hearthstone, actually had many bots running on the ladder for a time. Their goal was grinding, but even so, a number of them was better than a significant portion of the human playerbase. With the recent advances in artificial intelligence, computers are not that bad at this kind of task.
Overall, I don't disagree with your main point though. I have no qualms automating boring and repetitive tasks in non-competitive games. And if a competitive game has those parts, I'd probably avoid playing it. I'd rather spend my time coding than wasting it grinding because it's part of some game I otherwise enjoy. I feel it is indeed a more productive use of my time. I wouldn't go as far as judging other people who like the grind though.
If you get a competitive advantage from doing something like grinding, which computers can do better and more tirelessly than humans, and humans tend to dislike, then inevitably you will have cheating. (e.g. WoW)
If on the other hand the competitive advantage is from working out a strategy of in what order to play your cards to maximise your chances of building up your strength while attacking the opponent and yet keeping something in store for surprises the opponent may spring on you - a really complex strategic task - then that's something people enjoy doing and the computer sucks at. (Hearthstone)
People may be addicted to the first kind of games, but is that something that should be protected? It's kind of similar to people addicted to slot machines... sad, a reality we have to accept, but not something we should expend vast amounts of intelligence trying to sustain.
Of course, there are people who will do it for the money, and don't stop them, but realise that they are basically just a few steps short of people refining formulae for meth to make it more addictive - the fact there's a business case that exploits a human weakness doesn't mean it's a productive use of intelligent people's time.