It isn't a case of what I'm doing, it's what they do--and the reason I don't use them!
XX.X% passed is not the only information you get out of a T::B based test suite. It's certainly not the information I'm focused on when I'm developing.
All I'm looking for is whether the last test I wrote passed or failed. Personally I find that the existing tools give me this info pretty easily. Especially now that Test::Builder displays the test description so that it can be read without dropping into verbose mode.
The only place I find this information more tricky to find, sad to say, is with my own Test::Class - and I'm working on fixing that :-)
This isn't to say the pretty numbers and statistical summaries are completely useless. While it's not of much relevance during development, it can be a useful diagnostic tool at install/distribution time.