[chryuop]

As per the original thread I guess what he tried to do was using the adjective in both his uses:attributive and prdicative. He made a little bit of confusion with the demostratives, but I assume what he wanted to write was:
この時計は高いです　=> kono tokei ha takai desu.
and
これは高い時計です => kore ha takai tokei desu.

As per the question of TaeKim I might not be the best one to answer this, maybe a native would be more appropriate. However, in TaeKim site he states in the beginning that his course is not aimed at polite/formal speech. What he wants to offer is a more "friendly spoken" Japanese. True the copula だ can never be used to support an i adjective, but the です yes. I think what TaeKim wants to get at is that in that case the です part more than copula has the role of a politeness particle, thus since he offers as more friendly inclined speech he prefers to omit the です at the end.