That really is a problem for anything bandwidth constrained, even today. They're even trying to replace RSA at ~2kb per key. Part of it is also the human fact

That really is a problem for anything bandwidth constrained, even today. They're even trying to replace RSA at ~2kb per key. Part of it is also the human factor. Crypto is way easier if your keys are short enough to write down. You don't really want to be moving keys around on flash drives, it's hard to secure erase files unless the drives themselves are encrypted.