One strong muscle boy story could be about a young boy who was bullied at school for being weak. He decided to start working out religiously. He lifted weights, did bodyweight exercises, and followed a strict diet. After months of hard work, he not only built an impressive physique but also gained the confidence to stand up to the bullies. His story inspired many of his classmates to also take up fitness.
One benefit is better health. A Muscle Mom is likely to have more energy to take care of her family. For example, she can easily carry groceries and kids without getting tired quickly.
Well, it's hard to say for sure. The concept of 'porn-like' is quite subjective. Some might consider certain novels with excessive sexual descriptions as such, but it depends on individual perspectives and cultural standards.
In many places, 18+ porn comics are considered illegal. This is because they can have a negative impact on society and violate moral and legal standards.
The main distinction of porn with a story genre from regular porn is the presence of a coherent narrative. Regular porn often jumps straight to the sexual action, while the story genre tries to add some kind of story framework around it. But in the end, both are adult-oriented and feature explicit sexual content.