Something is always better than nothing.
An example: A couple of years ago my brother came down with some horrible sinus infection on a Friday late afternoon and it would have been Monday morning before he could have gotten a prescription for antibiotics i.e. he'd have been in dreadful shape. As things turned out, I had ready supplies which I keep around mainly in case the animals ever really nuke the region with anthrax or some such, and my brother was pretty much good to go the following afternoon. He now keeps his own supplies around.
For that matter, were you a farmer, it might easily occur that both you and your horse needed the same antibiotic on the selfsame day and you might easily discover to your horror that the medicine for the horse cost a tiny fraction what it does for you. I prefer SSM to trying to convince anybody that I'm a horse...