Isn't screen recording built in to windows, macos, ios now? Why pay for a separate tool?
I use quicktime to record screencasts all the time. The biggest issue I have is having to upload the video to youtube to easily share it. They are usually too large to just email around.
Yes screen recording is built-in, but something like Screenflow allows you to do a lot more, for example adding other audio or video (like camera for example), adding transitions, effects, annotations etc. This won't be important if you literally just want to record your screen, but if you are publishing anything these sorts of tools are useful.
