Taken altogether, they are helpful because they allow someone with little technical expertise to at least have a snowflake's chance in hell of recognising programing talent. If someone is enthusiastic, has a broad technical skill set, has been programming since before uni, loves to talk about the latest bit of technology he's picked up, is articulate, smart, learns technical stuff by himself, and has a tendency to work on side projects (rather than having all his experience on the CV), then they're far more likely to be a good programmer than not.
Remember, a business guy is effectively flying blind. I can sit with someone for 15 minutes and tell you whether they're a good hacker or not without having asked a single technical question, but someone with no technical skills cannot do that - nor can they figure out how to recognise someone like me to ask me to do it for them. They'll get fooled by certification-laden "software architects" who haven't written a line of code in years and will happily help them hire a football team's worth of mediocre programming talent.
I put together this list over a year ago to help non-technical people in this situation, and others must have found it useful, since over time it's accrued some 300'000 visitors and been linked to from pretty much everywhere.
If you feel you can come up with a better list of indicators, please do so, I'll be the first to vote you up.