Signatures seem to be completely useless. Like you, my signature has devolved into a squiggle that is never the same, and it has never mattered.

I remember experimenting as a bored young adult with my first credit card, before tap to pay, when you often had to sign with a stylus on a terminal (in the US) - I would sign something different every time, sometimes nonsense, sometimes a little drawing, sometimes writing “Obama” or “Einstein” to see if I’d get a call from my bank or something - never did.

Maybe there was an era when actual matching signatures mattered, but it seems long gone.

I guess if you’re a celebrity signing autographs then it matters.