Well, the web novel often has a more raw and unpolished feel. It might have some ideas in their early stages. The light novel, on the other hand, usually has better production values. For example, it may have more detailed illustrations and a more refined layout. Also, the light novel might have some parts rewritten or adjusted for a wider audience compared to the web novel.
It depends on what you like. If you prefer the original, unfiltered ideas, the web novel might be better. It gives you a sense of the story's evolution. But if you want a more polished product with nice illustrations, the light novel is a good choice.
It's hard to say which is more popular in an absolute sense. The light novel has a certain level of popularity because it is more accessible to the general public. It has a physical presence, which makes it easier for people to discover. However, the web novel also has its own dedicated fan base. Some fans who are more into the original and unedited version of the story prefer the web novel. But overall, in terms of mainstream popularity, the light novel has an edge.
Well, the Konosuba web novel and light novel differ in several ways. For starters, the light novel usually has better quality control in terms of editing. This means fewer grammar mistakes and a more coherent flow. The web novel, on the other hand, may have a rawer feel to it, which some fans might prefer as it gives a sense of the story's initial creation. In terms of plot, the light novel may streamline certain aspects. For example, it could simplify some of the convoluted sub - plots from the web novel to focus more on the main story arc and the characters' development.
The Konosuba light novel is not a fanfic. It has its own unique plot, characters, and world-building developed by the author's imagination and creativity.