There are forms of hydroelectric generation that aren’t damaging to the environment. We just need to actually be aware of the consequences and perform an environmental risk assessment. I think this is a requirement for new installations in the US, but I could be wrong.

They aren’t forms of energy storage on their own. Just like batteries aren’t a source of energy on their own.

While it can be used in localized electrical power generation, this isn’t exactly best suited for just that. According to the video, the typical household uses 60% of their energy towards heating on average. This type of battery would already be storing thermal energy in the form that you need for this, so any conversion losses would already be accounted for; it would just be radiative losses while distributing the heat.