While I agree that posting a beacon with your location in a survival/prep situation would in most cases not be the best move....
I can think of a number of somewhat practical reasons to have the equipment and know how to use it, especially given the fact that it is currently used by a number of individuals/organizations.
1. Not everyone is going to be worried about posting their location out there, if there is equipment/protocol available that can potentially tell me where other individuals are in my area why would I not want that. I do not have to broadcast a beacon to receive beacons from other individuals. Also depending on hardware involved it would be conceivable to write software which could alert me of a beacon approaching my location (again without having to send a beacon myself)
2. No matter how prepared you are there is always the possibility of getting in a situation where your life depends on someone else finding and helping you, in other words most anything that would lead to a survival/prepper situation could also easily lead to a SAR situation at some point.
3. With an understanding of the technology and protocols it theoretically would be possible to use some level of encryption or obfuscation (you could skew the coordinates by a certain value) to make use of this technology within a trusted group. (I understand using encryption in this way is against FCC regulations but in a true SHTF situation a situation from the FCC is the least of my worries)
4. If there are "emergency services" individuals making use of aprs then I may want to be able to monitor their locations, whether to find them for some reason or to avoid them, either way.
5. In a true "world as we know it has changed" scenario there may be reason to set up meeting spots for trading or whatever (this may not be overly practical)
6. In a scenario where supplies are of vital importance, a system could be setup, for example in a radio in a supply cache somewhere, or in your vehicle, so that if the location of that cache or vehicle changed ( without you changing a setting first) that it would then start putting out a beacon, allowing you to track your stolen stuff.
Some of these might be a little far fetched, but I would rather have the equipment and the know-how than not. Keep in mind that just because you have the capability does not mean that you have to transmit a beacon with your location. Also you can actually send out a beacon that has whatever location you want, ie you can draw an individual to a certain location, send someone on a wild goose chase, any number of things.....
All this being said I can think of some current uses for this technology, I spend alot of time in back country, and emergencies do happen.
Also if I have the ability to relay my travels back to my computer I may be able to later use that information to create maps that may be useful to me in a SHTF situation (Yes I know there are other ways to do this, but if I can just carry my radio in the woods and it does it all for me, as opposed to also having a separate GPS with limited memory and I have to remember to copy my track off before it overwrites and ... ... ..)
Anyway that is my 2 cents based on what I understand of the technology at the moment, would still love to hear from anyone that is making use of APRS in any way, or has any plans for it beyond what I listed ( or comments on any of this ).