The LBMA is a global authority on the standard of gold and other precious metals. There are numerous authorities on gold quality and best practice for dealing with gold such as the Shanghai Gold Exchange but the LBMA is seen as the benchmark, in the US and worldwide. All bullion banks trade LBMA certified gold.
By certifying gold, its provenance and history can be proved. This means that the owner does not have to worry about the gold coming from a non-reputable source or that it has been stolen. LBMA also helps ensure standards within the mining industry. Gold regulation is one example why it is seen as a safe and globally understood asset, in contrast to an investment such as cryptocurrency which is unregulated and can be potentially fraudulent.