Lots of folks seem to like non-magnifying (or low magnification) red-dot style sights for their defensive rifles. While these do have some advantages, I prefer a variable power telescopic sight for civilian defensive rifle use.
I see a rifle being used by a civilian for defensive purposes in a situation of temporary breakdown of law and order. Possibly to protect one's own property, or possibly for neighborhood area defense (banding together with the neighbors) against looters, etc.
In such a situation, it is going to be vitally important to identify a threat as far away as possible. Is that person approaching holding a hand gun, or a cell phone? Is that a rifle, or a walking stick? As we age, a telescopic sight can help prevent a tragic mistake - and can help identify actual threats at distance.
Of course, in such a situation, it would be a good idea to have a set of binoculars for general scanning purposes, since you don't necessarily want to point your rifle at someone that you're just "checking out." But having that magnification makes it easier to ensure you have good shoot/no shoot data right before the point of no return.
For close range use, a variable power scope can be dialed down to a low setting - reserving the higher settings for situations where it is needed.
So, for me, I prefer a telescopic sight to a red dot.
Thanks for reading.