I know this is an old thread, but add me to the club! I started using the Dunlop L white thumbtacks back in the 80s when I started playing. For me, I switched because I would get a cramp in my hand from gripping a regular pick too hard, plus I would drop or lose them. Switched to a thumb pick, using it like a regular pick. I stopped losing them, still have one from the 80s, and later, when I started to learn to play with my fingers, it was nice to switch up without having to put down a pick, or switch midsong between pick and finger style.