AFAIK, most receivers will output and allow input of almanac data, but generally only in their own binary protocol. How long the almanac remains valid for is another matter that I'm sure that Derrick could answer.

Writing track points out to disk could have uses:
Survey - although the receivers/antennas we are typically using aren't up to the accuracy of proper survery units, it still might be useful/fun.
Map making/calibration.
Road Trip Logging.
If live routing ever becomes a possibility (the map data issue obviously needs to be resolved first), then track logs may be useful for retroactive routing validation.
It'd be cool to be able to 'mark' a place for attention, much like you'd mark a track for attention. How many times do you see an unusual place or shop and think "Must remember that's there...", only to forget exactly where it was? Or stop on vacation and take a photo of a wonderful vista, only to forget exactly where. If JEmplode could check a known directory, and find a date/time/position log, and the route taken to it, then you could process that information, give it a name and reupload it as a normal route, or use it to help label your photos.
Custom route creation - if you know a better route from Exit X of I95 to your house/church/whatever, than mapquest/mapsonus/whatever can find, then you could drive that route, and then retroactively use it to create driving directions for friends/relatives/whoever - including typical timings.

So many possibilities.