(but for actual drinking water, smaller springs are preferrerd and can be found almost everywhere, except the dessert, too)

So you have drinking water - and can do extensive fishing, in the river as well in the sea - and in the very fish rich area in between.

Also with a river you can more easily connect inland.

(have you never played civilisation?)

You can be next to both.

Coastal settlements provide excellent food sources, and greatly limits various health issues (lack of salt, iodine, …). Consuming fish blood would also help, it’s going to be much closer to isotonic than seawater.

Depending on land structures, coastal settlements would also often benefit from much higher precipitation rates, providing freshwater. That’s essentially the story of Polynesian settlements, islands would be settled if they either had natural springs or enough precipitations.