A good deconstruction points out blatant flaws of some trope (conventionalised storytelling pattern) or even a whole genre; often the ones people take for granted. And in the process, it encourages the subsequent works to evolve, refine, diversify.

I'll give you an example. In isekai anime/manga/light novel series there's the "summoning" trope: one or more natives of a world do some magic or divine mumbo-jumbo, so the MC (main character) gets transported from another world (often Earth) into the first one. Often because those natives want the MC to do something, a "quest", like defeating the demon lord.

But wait a minute. They're kidnapping the MC from their home world, for some quest the MC has zero to do with. So odds are the summoners are really shitty people, who shit on basic human rights like freedom. And they'll value the MC not as a person, but as a tool for that task; for example if they want the MC to kill the demon lord, the MC will get judged by how strong they are.

If the trope is played straight, all of that is glossed over; you accept it as part of the universe of that work, and that's it. But the issue is so blatant that a lot of series popped up, deconstructing that trope; e.g.

• Chillin' in Another World with Level 2 Super Cheat Powers — MC is supposed to kill the demon lord, but his fighting potential didn't pop up as soon as he was summoned. So the king dumps him in a forest: out of sight, out of mind.
• Failure Frame — the goddess who summoned the MC is a fucking piece of shit, to the point she ranks the summoned heroes (yup, there are many) based on their powers. The MC got an apparently shitty power, so he gets dumped into a dungeon full of monsters to die.
• Nidome no Yuusha — once the MC kills the "big bad", the princess who summoned him kills the MC, in a mix of prejudice and ruthless pragmatism.

And so many others. In turn, this forced a lot of series to handle the summoning trope in a more acceptable way, like:

• Cooking with Wild Game — summoner? No need for that! The MC is in Japan, then he's in another world, and both the MC and readers get puzzled on why that happened. That's it. And he isn't in some quest either, except the one he decides for himself, because he's grateful to the people who gave him a home.
• Risou no Himo Seikatsu — there is a summoner, but she's a fairly reasonable person. She summons the MC and gives him a choice, that TL;DR to "if you don't want to stay in this world, I'll send you back to Earth tomorrow".
• Headhunted to Another World — the guy is summoned by the demon lord, who's pragmatic but fair. And the demon lord didn't do it because the MC got some amazing fighting power or whatever, but to perform the same tasks as he did in Earth as a sales manager.

So, note how the isekai genre got way more diversified than it was, simply because of that deconstruction. And even works playing that trope straight at least try to justify it better.

But it isn't just isekai, or this trope. Deconstructions in general are like this.