Found a tube of vegemite in one of my MRE's (Australian issued), it came with the one with Lamb with Vegetables, well all of them come with vegemite, mine just happened to be that one... Unfortunately no peanut butter. I wondered what it was but everyone set me straight.
Agreed it's a no brainer, peanut butter's better.
I guess you have to develop a taste for it.
Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.