Only that that's a sensible amount to allow to collect, since it never has to be subdivided.
If you used one tooter to smoke the whole 3.2 g., then you'd have to make at least a second to smoke the 0.8 g. you caught, and a third to smoke the final 0.2 g. So you would save 7.5 cm. of foil, at the expense of a more complex smoking procedure. You'd also have a tooter and a wrap left over. Come to think of it, if you were to dispense with making a wrap on the last-but-one day of the original stash, by simply melting the final 0.2 g. straight onto a plate instead of wrapping it, then you could even save a further 7.5 cm. of foil, since the leftovers now amount to two wraps and a tooter .....