This is something important to remember. You need to have enough credits in your balance to cover your rebuy cost. If you are killed, and you don't have enough in your balance to cover the "insurance excess" (rebuy cost), and the loan isn't large enough to cover the difference, you will end up back in a Sidewinder with 1000cr to your name (but you will still have any ranks/permits earned). The rebuy cost is a small fraction of the cost of your ship, so it is always worth making sure you have enough to cover it. For example, my Anaconda in her current configuration is worth over 420Mcr, but the rebuy cost is (only!) 16Mcr (and I have over 75Mcr in my balance).
Players wonder why this is in the game. To my mind it is so that players weigh up the profits/risks consequences.
