Mine can detect leaks, pump failures, problems with water clarity and orp, ph and temp.
It then can shut off potential leak points in area of leak, turn on back up pumps, turn on back up heaters (or cooling fan kill the doser or auto feeder, turn the lights up or down all while i am away and then notify me of what transpired.
It can do the water changes itself, run its own ato and ro/di water do randomized water and lighting like you wouldn't believe, simulate the seasons and weather and even send me pictures.
It also plots my water tests, par, probe readings on graphs.
If a leak does happen within the water proof stand, after pumps that can cause leaks are shut off (and wavemakers and display heaters switched over), it can activate a sunk pump and empty the water out of my stand.
If you open a door the lights come on Nd if anyone opens the doors ar canopy while i am away....ill know and can even photograph it.
One controller runs 2 tanks, 2 ato Resovoirs, , a salt mixing station, ozone, a nitrate reactor, dosers, AWC,and cam easily run more.
The only thing ive had legit issues with is the salinity probe.
With the time it saves i alwaya have time on my hands to keep those filter socks changed, feed frozen foods and clean the glass.
I have a big red panic button inside for the wife that puts the tank in a limp mode that can keep the fish alive for weeka even if pipes are busted.
Another single button stirs the tank in a way that would be dangerous to lps but is great for maintenance.
I could go on....you get the point though.
Seems pretty "useful" to me.