MRE meals are handy things to have around. They are quite popular with so-called 'preppers' who stock up things for disasters, even the supposed end of the world, but with good reason. MRE meals, such as one from XMRE, are easy to prepare and provide nutrition for service personnel in the armed forces while out in the field. They require no refrigeration and can last years in storage, making them a great emergency supply.
Preppers aren't the only ones that enjoy them. Many veterans used them while in their respective services and learned to appreciate the flexibility and security that they provide, so they stock up on them just in case. Every household should have at least three days worth of nonperishable food around in the event of an emergency, and MRE meals fit the bill nicely considering how long they last.
Some who spend time away from home find MRE meals to be a godsend. Particularly for someone that might go hiking or camping on their own or with just a few others, MREs are a chance to have plenty of nutrition for their adventure without wasting precious time outdoors cooking and cleaning. It's less weight to pack when deep in the wilderness.
MREs are even used on the high seas. Those spending a lot of time on the water might want to focus their energy and efforts on the actual activities taking them out to sea, and if they are going to be out on the water so long that perishables won't last, then MREs become dining that suits their needs for long-lasting food quite well.
Submarines in the Cold War carried them quite a bit too. Fresh foods would eventually run out, and MRE meals would be handed out at times for quiet eating, as mess hall activity might trigger enemy sonar.