I just run across this today:
http://discuss.joelonsoftware.com/de...joel.3.7054.16
which basically asks the same question. Pondering this, I came up with this analogy:

All the die-hard Amatuer (Ham) Radio people will continue to preach about all the reasons to learn Morse Code even though it is easy today to get an advanced license without ever hearing a 'dot and dash' sequence. There are only 26 letters in the alphabet, and if you learn one per day then you will have it mastered within a month... so why not do it? Voice transmissions take up a large bandwidth. When your entire neighborhood is talking and you can't find a clear channel to use, what are you going to do? If you know Morse, you can squeeze yourself into the airwaves.

Here is an example of someone putting their knowledge of assembly language to good use. http://invisiblethings.org/about.html Through all her talks, writings, and interviews, it is clear she *really* understands computers, operating systems, and the software that runs on them. It is also clear that she has developed a greate deal of competency in the understanding of assembly language. Yet, the programs she releases are not written in assembly. One does not have to produce assembly applications in order for that 'machine-learning' knowledge to be valuable.