The strap button is never electronically connected to anything at all. Connecting yourself to it cannot help. The wire needs to go to something actually connected to the amp’s signal ground. The jack barrel or the metal part of a cable plugged into it, usually pot shafts, the bridge, etc, BUT…
It is NOT A GOOD IDEA to permanently fasten yourself to anything connected to the amp chassis!!! Any failure in the amp which puts a high voltage potential on that chassis will then put that potential on you and there are a bunch of ways for you to create a path to ground such that a significant amount of current flows through your bag of wet meat. If you’re lucky, something else acts as a fuse before you do.