TL;DR: mAh is not a unit of energy. Energy = Capacity * Voltage (mAh * V). Industry should use Wh (or Joules, which is the same unit type), instead of mAh.
And Ah is a measurement of charge, it reduces to Coulombs. Amps is couloumbs per second (Q/t), if you multiply by time again you get (Qt/t) which is just Q, or charge.