I find this discussion really interesting, because I think that the majority of you is actually NOT using REAL butter.
I have a source for real butter, it is very expensive, made by some Amish farmers and sold in a specialty store 20 miles from where I live. Once in a while I am getting myself that luxury, but I can't afford it often. It is over $4 for a piece.
The national branded "Real Butter" pictured in the OP is not what it pretends to be. I once was involved in a study about this, and so I know it is "made with real butter". I have forgotten the percentage of how much butter actually must be in that product to be called "Real Butter". There is actually legal legislation about things like that!
Products do NOT need to be what the package is promising!
Example:
"pure olive oil" must legally contain 49% Olive Oil in the EU, but in the USA it only needs to have 25% olive oil. The rest oils they won't tell you! Obviously, the simpler buyer will go by the name and think "pure olive oil" is what it sounds like, but no, he is being fooled.
I came from Germany 10 years ago, I have all my life used butter to cook and bake, so I knew how butter reacts in use. For example, I know how butter looks like when melted.
When you take a stick of store-bought (regular) butter and melt that here, it will look and taste completely different. There is a lot of water and who knows what else in it.
So, this talk about "Real Butter" is a bot off the wind, because most of you will not likely have easy access to real (natural) butter.
Of course., margarine is a toxic product, but I tend to believe that this industrial butter is nothing else than a kind of margarine! What now?