The traditional approach to copyright restricts the freedom to copy works, and in contrast, copyleft seeks to use copyright laws to expand the rights and freedom of people in IT. People use the concept of copyleft so that anyone in the world has the right to use, modify or distribute both the original work and works derived from it, and no one could restrict this right. In general, it can be said that under copyleft, all derivative works should be distributed under the same license as the original work.
The choice of the strong copyleft can be made by developers who want to make an open-source software and allow people to reuse, distribute and remix their work but to keep this development free for everyone. This technique may have a strong effect of making resources and programs free, especially if the software under this license became popular and highly demanded. It may have an effect only if it will be implemented while publishing the first, original program. In another case, for example, when remixing a project, it will not be as successful and probably another license that the project had will not allow doing so. In my opinion, most of the big companies that want to use copyleft will choose this option, because the bigger their project was the more hard work was made. I don't think that developers would want to give their creation to the world knowing that others may resell it and make money, while the developers followed a good manner of copyleft and did not. Therefore they would want others also to follow that idea of free sharing and refusal from sales and implement the strong copyleft.
The weak copyleft choice may be based on the same reasons as the choice of strong copyleft, but with the addition of some exceptions. Especially in the case of creating software libraries. In this case, it more depends on how the product will be used than following the strict rules as in the previous type of copyleft license.
The smaller the project is, the lesser work was made and the easier the developer may let his project go. That means small projects may choose no copyleft at all. This option brings most of the freedom for the users because it allows them to freely use code, remix it and make a profit out of it. This may be the case with enthusiastic people who write small pieces of code, experiment with them or really generous developers who devote their software directly to society.
Used materials:
(May 10, 2021). “All About Copyleft Licenses”. Fossa. (Access date: 06.03.2022). https://fossa.com/blog/all-about-copyleft-licenses/
(February 09, 2022). “Difference between Copyright and Copyleft in FOSS”. Geeksforgeeks. (Access date: 07.03.2022). https://www.geeksforgeeks.org/difference-between-copyright-and-copyleft-in-foss/
Ayala Goldstein. (October 24, 2020). “Open Source Copyleft Licenses: All You Need to Know ”. WhitesourceSoftware. (Access date: 07.03.2022). https://www.whitesourcesoftware.com/resources/blog/open-source-copyleft-licenses/