Multi cursor edits feel nice during flow state, they let your brain stay in "edit" mode. However I only use them for edits of around 20-30 lines at a maximum.

Another use case for me is extracting interesting information from debug logs, where I don't want to think of a regex and the lines are similar enough.

I guess if you select the block and can tell it to only replace within that block, yes. As far as I know VSCode/Theia don't allow that. It's either click replace 20 times, copy/paste to a new file and replace all that way, or a quick multi cursor. I prefer the multi cursor. Especially when the language servers glitch out and don't let me rename the symbol gracefully, but there are many other use cases like the alignment as they mentioned.

VSCode can replace within a selected block. Though it takes an extra click. I see you point.