Is like a gun of an average NRA nut - totally useless for security, while advertising to the whole world that you want to get in trouble. These encrypted files on your hard drive have been transmitted over online services and shared with other people. It's far more convenient for police to get a warrant for online data and lean on those people than tinker with your computer. On the other hand, discovery of encrypted files that you are not willing to open is an excellent clue that getting these warrants and harassing your friends is a good use of police time.
Now, when it comes to passwords, your cipher might be 64 bit, but the space of words and phrases that an average person is able to remember is much smaller. Chances are, yours can be cracked with a map reduce task running on Amazon public cloud, for a small fraction of a budget DAs would allocate for a major case. If not, it's just back to harassing your friends and family. And it's not likely you personally are trained to withstand experienced interrogators and fitted with a dental filling cyanide capsule to swallow once you have reached your limit.
Most of those 9 cases probably came from lame police departments that just were not equipped/talented enough to do old fashioned honest investigate works. At the same time, thousands of criminals have evaded capture through old fashioned guile and ingenuity. If you want to evade authorities, for good or evil reasons, it's best to stick to simple things. An iPad hidden under a neighbors door rug is more likely to evade detection than an encrypted one in your house.