Because its cheaper than tankless. After a person averages the initial cost and installation of a tankless over the lifetime of the unit or time you will be at the dwelling it is cheaper to go traditional tanked.
I have never understood why in America we heat huge tanks of water 24/7. I thought it was stupid and wasteful then, and I still do now.
No need to heat water in an electrical heater 24/7 as there are many inexpensive electrical water heater timers available. Check your local home supply store.
Since then, I have never understood why in America we heat huge tanks of water 24/7.