I am incorrect.
Actually, when the Mac mini first goes to sleep, the LED remains on. The power draw when the LED is on is 4.5 Watts or 5.6 Watts, I suspect because the power tester is not very precise, measuring 0.9 to 1.1 amps x 5.1 volts. However, after waiting a little while, the LED goes off, and it draws 0.2 to 0.3 amps, or 1.0 to 1.5 Watts.
Idle: 4.5-5.6 Watts (LED on)
Sleep: 1.0-1.5 Watts (LED off)
IOW, there is still a little power draw, which I guess explains why after many hours sleeping, the SSD temperature is not room temperature.
BTW, the good news is since I've had this enclosure, it's never lost the connection during sleep. With my M1 and other drives (T-series SSDs and portable hard drive), I'd occasionally get a warning message that the external drive was unsafely disconnected.