Construction lines are very useful and second nature to architects and draftsmen. It is also great to be able to extinguish them all at once, as you can in SU. But there are times when it would be useful to be able to keep selected ones, say as reference centrelines. It is also handy that they show in LO as faint dotted lines.
So what I would like to suggest is an option when you invoke Delete Guides, say to Delete All or Delete Selected. AFAIK, you cannot protect them by having them inside Groups or Components as Delete Guides does what it says on the tin and deletes all, wherever they are.