The template is flat, the driver is in my kit already.
Scenario: I get a puncture, I fix the puncture there and then no matter what the weather (can't do the same with patches). Job done and I have no need to think about it again.
Scenario: I get a puncture, I change the tube, I have dirty tube to carry as I don't litter. I get home and at some point have to fix said puncture - got dirty twice.
Scenario: I get a puncture, I find puncture, I have to sand puncture (even more hassle on the moulding line), I apply the patch (self adhesive). Job done and I don't (usually) have to worry about it again.
Now scenario one and three seem similar - except in scenario one I never have to take my gloves off. Which in winter is a massive bonus. Been there, done that and got cold fingers. Now take into account that Brompton tubes are £6 each - it's a no brainer.