There are only a few situations where an NVME SSD block is of real benefit, and this is primarily in drives where the controller has been factory overclocked to such a point that it will thermal throttle without stronger cooling than a small heatsink or heat spreading sticker. This is more common with early PCIE Gen 4.0 drives. Another potential instance is in drives that are overheating due to a lack of airflow where they are. This can happen in builds that have very little airflow in the main chamber and an external radiator or with other obstructions in lower airflow cases.
It should be noted that using a waterblock on an NVME SSD that is not prone to overheating can reduce the write endurance by keeping the storage ICs cooler than is optimal for them. If you want to use one for purely aesthetic purposes, it’s possible to get around this with some creativity, however.