Of what real, practical use is electronics certification?
UL listing is most common in consumer goods, and appliances in particular. The reality is the consumer doesn't really care whether or not a product is listed. The people that care are the retailers and insurance companies. 

Consider a Wun Hung Lo toaster with so many corners cut in design and manufacture, it's a circle. Walmart buys a shipping container at $1 per piece, and sells them for $4.99, until someone's house gets burnt down by the shoddy design and assembly. Walmart gets sued. The alternative is doing the same thing with a UL listed design. The UL listed design is insanely unlikely to burn down someone's house because it's been tested torture tested to standards to prove it won't. Retailers are glad to carry such products and insurance companies willing to insure the manufacturers because the risk is much lower. 

That's not to say the UL label is a guarantee of safety. There are a lot of products coming out of China with fake certifications, including UL and CE. Just look at some tear downs of fake Apple chargers. They're criminally dangerous, but marked just like the genuine products. Only trust the marking if it comes from an authorized distributor.