Or did they simply want a knife able to hold up in the event of using it in a survival mode once they returned to earth and before they could be picked up?
BINGO!!
Although the blade design was such that is allowed usage with their "space gloves & suit", the main purpose of the "survival kit" was just that / SURVIVAL! The splash downs were not, or had the potential to not be, exact. The possibilty of over-shooting (or under-shooting) the deignated splash down area were quite real. Facing many unknowns was the thinking behind many of the pieces of gear that were included in the kit. The small compartment between the handle scales could house several small items, which might prove invaluable in certain scenarios.
I also believe they carried gold coins and a S&W "Air Crewman". Probably not a lot of need to go on a "spending spree" in space! I am certain that some other folks will be able to add to this but this is what I have been told.
Best, Capt. Chris