In its core, the SDK is a Node.js library available through npm that anyone can use on his project. You can use it locally on your computer, integrate it to your system or run directly in Actors on Apify. Its dedication to scraping and automation jobs makes it an ultimate tool for these kinds of tasks. It does all the hard stuff (managing concurrency, hiding you as a bot etc.) for you so you can focus on your particular use-case.
Definitely look through the awesome tutorial and documentation.