It really boils down to what one is seeking to achieve. If all you want is a digital camera, then yes, this is a colossal waste of time; if you want to approach it as a mechanical and mental exercise, solving a problem of your own design by whatever means you choose and are able to effect, then I'm all for it. Taking things apart, figuring out how they work, and redesigning, reconfiguring, and reassembling them successfully can be enormously satisfying in an academic sense, even if the end result is of little practical purpose.