It is not encouraged for students to apply and take part in both the GSoC 2021 and SoD 2021 programs as they are two very different programs with different focuses and skills required for success.
Google Summer of Code is a mentoring program where students still learning best practices and refining their coding skills are encouraged to apply and will have mentors guiding them through the development of their project.
Season of Docs is not intended for beginners, it is intended for people who already have solid to great technical writing skills and experience. Technical writers in Season of Docs aren't mentored, and instead need to be self-organized and motivated to figure out their plan for tackling the org's project with minimal guidance from the org admins and other community members.
However, it is encouraged for open source organizations to consider applying for both programs if the goals of both programs meet their organization's needs this year.
Best,
Stephanie Taylor
GSoC Program Lead