Well, of course, MY reason for making ammonium chloride was purely educational. But someone more scrupulous than me might want to react it with formaldehyde to come up with not-so-easy-to-get methylamine for the gingard meth synth you just translated, or for an MDMA synthesis, or even (eventually) to convert tropinone to 2-carbomethoxytropinone. Let's just say this person's interests might be very diversified.
Actually, SWIM is most curious about a particular anaolg of cocaine, 2-carbomethoxy-fluorophenyl-tropane. He heard it was 60 times more potent than cocaine. It's been a while since his last chemistry lab though, and references for it seem scarce, so he has a lot of brushing up to do before tackling that route.