I use FFmpeg for multiple streams and mux them into another container file format. Don't see what LosslessCut does outside of FFmpeg expect for the UI. The backend is anyway FFmpeg as another comment mentions. CLI haters I can understand, not me.
I at times am chopping up 2-8 hour videos with dozens of clips that are not pre-defined for me. I can do this with FFmpeg and I love doing most things from terminal but its a pretty hard sell when what you're doing involves something inherently graphical. I use FFmpeg for all sorts of things but it just doesn't make sense for editing such large videos on the fly like this.
