My 1970's house also had that system until I updated the heating and water supply about 5 years ago.
It will no doubt take many years before 'all mains' will be the norm but most modern buildings will be OK. I have seen some discussing examples of uncovered galvanized tanks in the past. Modern plastic tanks with close fitting covers and in less dusty lofts will be fine.
Originally mine just has a small tank above the hot water cylinder. But I updated that to a larger loft tank raised up into the peak in order to get an improved shower head. Then moved to a pumped power shower system. We are now on to a Combi which gives a great space saving.
We are now able to drink water from any tap to our hearts content. But we still use the kitchen tap as everyone else does.
If I remember correctly, storing water in the property was considered a good thing many many years ago because it gave everyone a reserve if needed.
John