I found the tests useful. They help show which areas of the N900 should be protected with various screen protectors/cases, how it reacts to dust, and water - all things that happen in real life. Sure, the results of the freezing water/snow test is probably as expected, but it clearly survived the less strenuous test beforehand. Suppose the test showed that a single drop of water fried the keyboard/affected the screen - that would be useful information.

He conducted the tests because his N900 was defective, as mentioned in the first video.