About not really cleaning the weeds, you can chalk it up to how MC can fast-forward and even skip a lot of farming steps due to plant goddess' blessing. He can insta-grow these plants with the plants absorbing the surrounding nutrients quickly, so burning the field is not really necessary if the "grounded" weeds can already get absorbed as nutrients.
Being able to skip farming steps doesn't answer why he's taking
more steps than necessary. Like how digging the soil up and plowing accomplishes the same thing, but they treat it as two distinct and necessary steps.
I also didn't say burning the field is necessary; I said it was a good idea. It would accomplish the same purpose for less work.
People also don't normally use weed burning in a forest; there's a high risk of the fire spreading to other flammable materials (like dry twigs and leaves) and structures.
People generally don't have magic powers to create fire.
It's MC's perk: the blessing made all the plants he cultivated far tastier than those growing wild.
What I said has nothing to do with MC's perk. That's about everyone else.
Certainly the Demon King won't mind his daughter being put to work in a field!
I have no idea how he would react. For the kind of fluffy nature of the manga, I don't think he'd object too much. Though he'd probably not mind her growing up a bit.
What would also explain this is the "everyone who goes from Earth to [another world] is smart and everyone in [another world] is ignorant" trope that is often over-abused.
That's pretty much what I was getting at. It's like how some people claim medieval people were filthy and smelled bad all the time. Like, did people not have noses back then? Is human progress not based on making things more comfortable for ourselves? If there's a problem, people would have tried to fix it, and if there exists a viable solution for the technology level, it's likely to be found.
Really, not only the MC, but possibly the Mangaka as well could be completely ignorant of real world farming. Far too often people don't research (or deeply research) their subject material...
That's the impression I'm getting from this manga as a whole.
The author seems quite deliberate in addressing the frequent complaint about brats being let off the hook just because they're cute girls. Normally you don't see that much focus on getting them to realize the consequences of their actions.
I really do like the double-take she did on reflecting on her actions.
