Well, seamark:type indicates that it is a seamark describing an object usually shown on nautical charts. The same feature can be a non-seamark object as well, which usually is rendered on a non-nautical chart. Typical example is a node with seamark:type=light_major and man_made=lighthouse. The feature can be named differently in either context, the lighthouse is named in name, the nautical light is named in seamark:name. It is now up to the renderer to decide how to display the feature and which tags to use. All these tags live on the very same node and thus “interact” with each other. The feature is not one thing, it is multiple things simultaneously and depending on what you want to do, you pick what you need. I do not understand where the problem is?