Avoid debugging.

Debugging is one of the most time-consuming tasks of the developer. So, you should try to avoid it as much as possible.

One way to avoid it, is doing small steps. The idea about TCR is to encourage you to do small steps, while tests pass. When small, is, probably, just a few characters. If you can split the development in such small steps, why to worry about throwing a few characters?

Even more, in TDD, the recommendation when you have troubles making a test pass is to revert it. And try a different approach. TCR does it for you. It is not so different, in fact.

For my experience, we usually do not fight with the limits of bits, and if we do, those limits are themselves a test. I think that you have stretched a little bit the example. For the rest, I consider that it is an excellent practice; it is because the reason number 2 why TDD does not work for several people is because they do not know how to do small incremental changes while passing tests. And TCR is a great way to train. The reason number 1 is that they use QA unit tests instead of TDD unit tests (that are nothing alike except for the name and the test tool). But for that, TCR does not help.