The person that owns the address used vanity address generator to generate the address with high computational power equipment. If the person generated it with the right vanity address generator software, the address is very safe just like the normal bitcoin addresses.
I think I am also learning from here and I will also want to ask something more here to know, now this vanity wallet creation does it comes with seed phrase or key or password. And is this the first type of wallet address creation methods?
From your statement that is what I understood.