When I go for a wander I like to take one or two sliced of prepared "wet buppy" and a takeaway box of mashed bread and bran; maybe a slice or two of fresh bread to chew, for added enzymes, and a bit of white crumb for if the mash gets too soggy, so, though I've not run out yet, lately, it can be a close-run thing. Hence the lightweight insurance value of a slice of the Magic stuff.
The point I was trying to make without being too blunt about it, though, is that if so notorious a tightwad as I makes sure they've got some in the bag, it's probably good stuff.
It also gives you a change bait - if they're having the bread properly, you won't need the magic stuff, but if they're in need of persuasion - "Eet's waffair theen" - then a smidgen of Magic Bread can be heap powerful medicine.
If I'm trolleying a shedful of kit to sit in one place, I'll make dam' sure I have enough bread for the trip, but I still like knowing there's a change I can ring without having to switch methods completely.
OK, confession time - I'm so mean that, if I think it's time to try the Magic bread, I break a little bit off the corner of each flavour I carry, soak them, and find out which one works before committing a whole slice to the water.