Question

how are tides useful to us?

Answer 1

Tides are the cyclic rising and falling of Earth's ocean surface caused by the tidal forces of the Moon and the Sun acting on the Earth. Tidescause changes in the depth of the sea, and also produce oscillating currents known as tidal streams, making prediction of tidesimportant for coastal navigation.

Answer 2

Without tides, it is highly unlikely that, at some point in the past, ocean life made the transition to the land. That’s the most important thing.

Tides are also important as a potential source of energy production through estuarial facilities. It is costly to implement, but is free after that (apart from maintenance), i.e. the moon isn’t going anywhere soon.