Some would say signatures are used to verify I have agreed to something. Others use signatures as a ceremony where the signing in the presence of witnesses (as

Some would say signatures are used to verify I have agreed to something. Others use signatures as a ceremony where the signing in the presence of witnesses (as per the article) is merely like the gavel coming down in court. It signifies (ahem) the process is complete and it’s the witnesses that make it irrefutable, not the shape of my squiggle being inherently unique to me. But the bank still wants my signature on file for security reasons. Can it be both — a biometric and a ceremonial action — or is the bank just engaging in security theatre? If it’s a biometric, why are some people allowed to use X as their sign?