They can, but the question becomes, "do you see the value in it?" The extra cost in the eddy test starts to weigh in on the value of the tank. Would I continue to use them without testing and my own compressor? NOPE!
Aside from the current pandemic shortage, aluminum tanks are fairly inexpensive new, so why bother with the issues of these bad alloy tanks?
As to your 72 steels, if they are liner free, they are a nice tank. Yes, the 1/2" valve gives some pause. Don't fear diving a j-valve, just put it in the down position and it is just a tank of air. $70-$100 for new 1/2" k-valves is a tough pill..
Honestly I don't think they're worth it, but wanted to get confirmation. I don't use AL tanks. But they were free so I took them. I figured I'd come here later.
I went to pick up a set of steel 100HP, the set was $75, so when he started throwing stuff on the truck I didn't complain.