Generally without independent testing and certification on a safety critical item, you get a market where there are some well established companies who products unquestionably meet the safety standards. These tend to become rather expensive products, but what many experienced people use, because it is definitely safe.
There will be some really cheap stuff sold that absolutely does not meet the safety standards, and nobody with much common sense will trust or use these products.
But then you get reasonable priced items from no-name brands that might meet the specs, but nobody really knows, for all they can tell they might just just be unsafe junk just like the cheap stuff.
Since your life may quite literally depend on whether the product meets the safety specifications, is it worth going for the sanely priced stuff, not knowing if it is really safe, or pay for the overpriced stuff everybody knows is safe? If you ask somebody knowledgeable about the field, all they can can do is recommend the overpriced stuff.
Whereas if there was independent testing and certification, the knowledgeable people could tell you that it is fine to get any product certified by , if money is not a significant concern, you can go for the trusted expensive but well established brands, but if your budget is tighter, the cheaper certified stuff is still fine, and won't kill you, but might have other minor downsides like not looking as nice, weighing more than the higher end stuff, etc.