At least in the UK, getting a private pilot's licence did involve a couple of hours of simulated IFR. Not enough to do anything complex. But enough to turn 180, and be able to follow detailed controller instructions.
If you're up over, say, Iowa at night? Tons of farms, flat, lights everywhere? It's fine. Pretty, you can still see stuff, and short of an invisible power line for an off airport landing, it's almost like flying during the day.
Out in Idaho, in the mountains? You're pretty dumb to fly VFR at night. There's no light anywhere, lots of hard rock, and plenty of clouds that like to appear with no warning.
But, yes, fuel gauges suck. The problem is that even if you put something like a fuel totalizer in, you still only know how much has gone into the engine, not how much is left in the wings. I understand a loose or missing fuel cap will drain a Cessna's wing tank in about 10-15 minutes.
I remember coming across that as a specific design challenge to overcome. Floats don't read the same when flying upside-down.
Those who fly upside down on purpose tend to either not care about the fuel readings when upside down, or fly something modern enough. But I can't imagine an airshow performer is paying any attention to the fuel gauges. "I have a 15 minute routine, I have an hour of fuel onboard, and I'm surrounded by an airport, which is a good place for an emergency landing."
