Absolutely true.
For years I kept a self-made first aid kit in my purse, in one of the old metal band-aid boxes, that contained essentials such as fabric bandaids, Neosporin, gauze pads and tape, but also dental floss and needles (which can be used to sew wounds shut), butterfly bandages, burn pads, a mini Swiss Army knife with scissors, and even a length of rubber tubing, that could be pressed into service as a tourniquet. And of course, aspirin, Alka Seltzer and the like.
Luckily the only times I had to use it were for minor injuries, but since we sailed a lot. and a lot of things can happen far from shore, I was always glad to have it close at hand. And I was always amazed by how much I could fit in there.
I'm actually in the process of putting together another small emergency pack for my car. Always good to be prepared.
If I were on a boat, I would definitely have a lot more medical gear. The delay between injury and hospital is even longer of course. What's the worst injury someone had while out sailing?
Typically either drowning, or getting conked on the head by the boom, though obviously puncture wounds and/or deep lacerations, as well as burns, are always possible.
I've been hit hard in the head with the boom, during a sailboat race no less, which was no damned fun, but thankfully I was not concussed, which was a bit of a miracle in itself. It did, however, end the race for us, which I argued against at the time, as we were beating one of our regular competitors boat for boat.
We did have a larger more complete medical kit that stayed on the boat, which included a flaregun, emergency blankets and rations, splints and gear for more extensive wounds. Thankfully, aside from using the emergency blankets on one cold, becalmed night, we were never called to use either kit.
The kit I referred to above went with me everywhere in my purse.