The Casio G-Shock GMC-B2100AD-2A is one of those watches that makes more sense on the wrist than it does in a spec sheet. On paper, it is a full-metal G-Shock with Tough Solar, Bluetooth, 200-meter water resistance, and a fully analog chronograph-style layout. In person, it feels like Casio took the familiar “CasiOak” idea and…