I've been using just my fingers this past 50 years. When I've kept the tube relatively clean, decently sanded and let the glue dry enough and located a large enough patch correctly, they've just about always worked. I'm hearing now I've been doing it wrong a very long time.

To me, fingers have it all over those tools. Completely weight weenie-friendly. Very accessible. Take up no space in my tool bags (and I don't need another set for each bike), never get lost or misplaced, work in just about every situation I've ever ridden in. (Well, not so well on the very coldest days but in those days, I rode tubulars in the winter, partly for that reason. Also cyclocross tires, which in those days were all tubular, make excellent snow tires.)

And last, I guess I should just read the Rema instructions to see what I should have been doing.