According to IgnacioFDM
https://github.com/alliedmodders/amxmodx/pull/380, set_task has some performance issues, like using a linked list instead of std::vector or not ordering tasks by execution time instead so you don't iterate over the entire task list every frame. Unfortunately, the PR has never been finished and it also fixes some precision issues. With today's computer will be this an issue? I don't think so, it all depends on what the set_task is being used for.