See this Onyx training video on Load: https://youtu.be/yrbG1E9Ub2g
(around 1:36 he goes over Loading from a cue)
Watching a bit of that video made me realize a ‘copy cue X + Y @ cue Z [merge]’ (quick and dirty merge) would have to make a lot of assumptions about how you wanted to combine/merge the two cues:
Include Fx and Time or just Base values? (And same for both cues, or different for each?)
Include active or inactive fixtures from each cue? (And same for both cues, or different for each?)
If both cues contain some of the same fixtures and parameters, which value goes into the merged cue (the value from cue X, or the value from cue Y)?
Etc.
The assumptions it made may not be the ones you want/expect, so you’d end up using Load to have more control and understanding of what was being merged into the new cue anyway. (Or the quick and dirty “copy [merge]” could give you a pop that allows you to make choices as to how to merge things from each of the cues… but then you’re essentially doing what is already available with Load.)
The assumptions would get even more impactful, and probably more confusing, when you want to “copy [merge]” more than two cues.
Just my random thoughts/opinions.