I have been hearing lot about working on one's strengths. It is also mentioned in the 4 Hour Workweek and it does make sense. But let's say I am good at design, does it mean I shouldn't learn programming (something I am doing right now)?

Even if one is not planning to master something that he isn't good at, does it make sense to invest or waste time on it? Our brains are effectively good at certain things and rather mediocre in other things but it does learn things and thus changes if persistent effort is made.

Over to someone who wants to chip in with some better explanation.

Thanks to OP for sharing the article though.