Difference between scattere plot vs Tree map?

TreeMaps: Treemaps we will display data in nested rectangles.We  use dimensions to define the structure of the treemap, and measures to define the size or color of the individual rectangles.Treemaps are a relatively simple data visualization that can provide insight in a visually attractive format. Treemaps cannot accommodate more than two measures—one to control size, the other to control color. Treemaps can accommodate any number of dimensions, but you can only use one dimension to diversify the view, by dragging it to Color.Other dimensions can be used only to multiply the number of rectangles in the view. 

Dimensions cannot be displayed in a hierarchy. We can not add the Trend Line in Tree Maps

Scatter Plot: Scatter plots provide an easy way to visualize relationships between numerical variables. In Tableau, you create a scatter plot by placing at least one measure on the Columns shelf and at least one measure on the Rows shelf. We can add the trend lines in Scatter Plot and we can show dimensions in hierarchy.