It sounds like an amazing way to learn hard concepts by following a progressive and clear track of knowledge, starting from first principles. Also, the presentation is clean and easy to read, nice job!
Thanks for your comment! I would say the main difference is that Qastor is aimed at tests that are manual by nature. I've seen that a common practice (at least where I work at, ha) is using spreadsheets to form a test matrix, and then referencing screenshots on Google Drive. The way Qastor works is by using keystrokes to gather the evidence and advance to the next test case, reducing the time it takes to compile the final report.
For example, I mainly used it for a POS system I worked on, where some of the tests couldn't be automated, such as verifying that sale tickets were correctly printed by thermal printers or doing visual UI/UX validations.