I didn’t fully illustrate my specific use/need to merge these columns, and perhaps I’m an outlier. But my issue may be a good example of other uses for spreadsheets, not anticipated by the developers.
I’m not using Calc as a spreadsheet per se. I’m using it as a design tool to do variable printing in Adobe Indesign. Most of the variable printing software wants to pull City, State, Zip from 1 cell, due do a specific peculiarity of zip codes starting with zero. Despite asking for, and illustrating how we need addresses formatted to print customer’s envelopes, we continue to receive multi-column versions from those same customers, and hence the need to combine those three columns. Until now we’ve done it by hand, and these can be hundreds of addresses/cells. So your formula is a god send - thank you, but my suggestion is perhaps like adding a “claw” to a hammer. Perhaps not first anticipated, but pretty useful once it became standard.