With CoreXY machines the Y axis has a much larger mass than the X, limiting the overall speeds that could be achieved. If Klipper had these settings separate for X,Y and Z, the user could tune each axis for maximum performance. Hopefully, resulting in shorter print times.
This has been discussed many times going back many years, and at least 2 pull requests have been submitted to add separate X and Y acceleration control. They have not been merged, and in reading the comments from developers on those pull requests it seem unlikely that this will ever be merged.