I don’t think that it will surprise anyone to hear that Capture One Pro is a RAW converter first, and foremost. In its early days (my first introduction to it was somewhere around version 3), it was only a RAW processor. The standard workflow was to load images into a session folder, demosaic the file, and allow you to make darkroom-like adjustments to it.
From there, you exported a JPG or TIFF and did what you needed to with the resulting file. Capture One did not concern itself with libraries, catalogs, keywords, or much of anything else. Put a RAW file in, get a nicely developed TIFF out. It was then, and may very well still be, the best RAW image developer available.
But times have changed.