But why is that multi-step process even necessary?

There should be an quick command-line utility to concatenate multiple video files according to exactly the timestamps the user has provided. It's such a common operation.

There's no reason that the tool can't simply do a streaming decode of multiple different file formats and concatenate the video and sub-second precision. If input video resolutions are different, scaling the smaller video to the largest resolution is what the user almost always wants.

I get that FFMPEG is a "plumbing" CLI tool, but a "porcelain" wrapper would be amazing!