From the promenade you are looking out. From Elliott Bay you are looking back, and the city arranges itself differently: the downtown towers stack into one skyline, the Space Needle separates from the buildings around it, and the piers you just walked read as a single line along the shore. The working port becomes legible too — the container cranes on Harbor Island are hard to gauge from land and unmistakable from the water.
On a clear day the Olympic Mountains close the horizon to the west, and Mount Rainier appears to the south when visibility allows. Neither is guaranteed; Seattle's weather decides, and plenty of good trips happen under cloud.