Plotly: How to define colors in a figure using Plotly Graph Objects and Plotly Express?

There are many questions and answers that touch upon this topic one way or another. With this contribution I’d like to clearly show why an easy approch such as marker = {'color' : 'red'} will work for plotly.graph_objects (go), but color='red' will not for plotly.express (px) although color is an attribute of both px.Line and px.Scatter. And I’d like to demonstrate why it’s awesome that it doesn’t.