An espresso machine is essentially a 1-2kW electric boiler, a compressor pump, some valves/actuators, and some PIDs, right?

Even if it draws 1.5kW constant for 24h/day that’s only 36kWh. That’s about ~$5 to ~$15 of electricity, depending on how mismanaged your utility is.

It costs less than an hour of labor to power an espresso machine for an entire day, the energy cost to pull a shot is negligible, pennies. The rooftop unit cooling and heating the coffee shop probably uses 2-3x more energy.