1. People enjoy watching a live internet human vs. human game more, when they can watch a computer judging the human moves and evaluating the position.
2. Few people enjoy watching live computer vs. computer games, even though the quality of play is much higher and the likelihood of a complex, wild position is much higher. Even if you care at all, there is little in-progress suspense; you might as well look back at the moves once they are over. How many other activities would we enjoy watching or experiencing less if they were done by computers?
3. The quality of play in a computer vs. computer game is so high it is often difficult for humans to tell where the losing computer went wrong, even if the spectator human has the help of a chess-playing computer.
4. I find only the very best computer (Rybka) of interest, although I do not feel the same way about the human players. Furthermore the fifth best computer is still much better than the best human players.
5. The notion of a computer chess tournament taking place "in time" is an odd one. You can play all the games back-to-back or simply use multiple copies of the programs and finish the entire tournament in a few hours; see #2.
6. Watching a computer play chess is a window onto a world where, once the opening is past (often, computers are simply told what to do by a pre-programmed "openings book"), there are many fewer presuppositions than what a human mind will bring to bear on the problem. It's a very good way of learning, in convincing form (the computer will beat you), how much your intuitions lead you astray. It's not just your "bad moves" which cause you to lose, it's also the moves which still seem pretty good to you.
7. There are nonetheless many computer moves which I simply cannot believe are any good. It does seem that every now and then computers get stuck in a "dogmatic trap," usually because of their limited time horizons for evaluation. Playing against a computer, you will do best in the early middle game and then progressively fall apart as its combinatorial powers destroy you.
8. You can watch chess computers play against each other at www.chessbomb.com. Click on "enter" and then TCEC5.