Good article Marat.

For the disadvantages, I have my two cents to add.

For me, if you examine the project in long run, maybe TDD could save some time. I mean if you count the debugging time, time to find defects or even fix the regression without these tests in the first place.

For the scope stuff, I feel you're saying more about unit tests? You can (and maybe should) use Acceptance Test-Driven Development instead. Basically write test from the end user's perspective, not from the developers point of view.