There are many nice and FOSS GUIs for the tasks ffmpeg is usually used for.
Handbrake is a great example for macOS, windows, Linux.
For more advanced video compression Shutter Encoder is fantastic.
Good old AVIDemux has a few other cool features as well, like cutting without reencoding.
There are also a bunch of straight up ffmpeg front ends as well.
Why do people use those shitty websites?
They show up as a fast and easy option without having to research, download, install, and learn to use a more complicated application.















The qualification is social proof, that you’re from at least middle class background. Meaning you have a little manners and know social codes.