The point is you can do it yourself, you don't need anyone else's guarantee.
In practice, it's more like a 75-90% failure rate if you're unfamiliar with ball-soldering techniques, which most are since it's been considered impractical to do soldering in the US since the through-hole days, and so there's not a professional tradesman class to teach kids. What does exist of soldering is stuck in the far past from an electronics manufacturing perspective.
Tl;dr: https://xkcd.com/2501/