Thats mind boggling... I'd like to read that reasoning about that! (I'm sure there's some German-language publication somewhere...)
Did they want each bullet to have a /64?
Well, bullets might move between routers, so they might change the Layer-2 network they are on, and thus might need their own independently routable address. Afaik it is bad practice to route anything smaller than a /64.
I have both a /29 and a /32 of v6 space, and unless my ASN achieves total global domination on a scale never before seen by humankind, it should last a good long time. :-)
What's enormous about an IPv4 /12? :)
When the German army requested an allocation of IPv6 address space, they were given a /28, but complained that 2^100 IPs is not enough for them and they actually need a /22.