I always see the display the first time I open the door. Subsequent times it's blank. Never used 120V, always 240.
You don't actually need to look at the display, the dash light blinks once in the lower 1/4 of charge, then blinks twice till half charge, then 3 times, and then 4 blinks. Solid on is full. (There's a phone app too.)
A slow single blink means delayed charge, and the horn beeps twice after being plugged in. One beep means charging right away.