I like the artistic aspect of "fish" tanks. (Aquariums)
I also like the fact that the entire environment is compact and self contained.
Shut-ins, children, old folks can all enjoy the beauty of a tank without too much muss and fuss-or exercise.
I have had all sorts of animals, wild and domesticated. Emus, peacocks, snakes, horse, pygmy goats, etc.
Groomed and interacted with wolves, and even young jaguars at a zoo.
Aquariums by far are just as entertaining without hands on. (well, some of my fish do like being petted)
As far as living things go, you are right, the color can't be beat. I knew someone who had a greenhouse and raised passion flowers-that came close, but no cigar