Yes, heat reuse is easier with water cooling since the losses are smaller, but even air cooling will produce warm water in the end. There will be coming regulations requiring a certain amount of heat reuse, but in a first step, this probably won't force direct water cooling.

For those regulations, there is also the important aspect of free cooling, i.e just using outside air as a medium or using an air-air heat exchanger like a Tokyo Wheel. Mandated heat reuse (without appropriate exceptions) would make those illegal, however in certain situations those are the best (environmentally and financially) methods of cooling. E.g. in a moderately hot summer you can use 20-30°C outside air without a problem, but if you would mandate heat reuse at that time, you would have lots and lots of excess heat on your hands with nobody buying it. So while some regulation will be coming, I hope and think that it wouldn't really issue a strict mandate to reuse heat and allow free air cooling, which would exclude direct water cooling.