Given the relationhsip between voltage and current to say that one tells you nothing and that only the other is useful seems to miss the point.
If you wait to look at your voltmeter until your battery is dead its not going to tell you anything. If it reads 14 while the motor is running your charging system is working. If it reads 12 while the motor is running you have a problem.
If it drops below 8 or 9 while starting you have a problem.
If you think a volt meter is useless that's your problem.
Just like the oil pressure guage and temperature guage, waiting until you have a problem to look at the guage defeats the purpose.
Learning the correct way to use the tools might make you better prepared than 90% of GM's customers, but ignoring those tools until you have trouble sure doesn't.
In a day where it takes 100 amps plus to support all the accessories on many vehicles using an amp guage to show what is happening means some real big wire running from the alternator to the guage.
I think that is a problem. But it can be your problem if you prefer.
