The main difference is that a TypedView is read-only, while an Entity is not. If you have an editable view (f.i. a db view that query just one table, and it includes the PK) maybe you want to make changes at code. If that is the case maybe you want to map it as an Entity.
A TypedView cannot have model-only relationships, thus cannot have PrefetchPaths. It might be that you want that. Lets say you have a special view SpecialSalesByProduct that you want to use along with your Product entity. You could map it as an Entity and create a model-only relationship with the Product Entity. Then you will have a Product.SpecialSales navigator that you can fill with a prefetchPath.
Normally you don't have to map a DB view to an entity, as views are normally intended just for displaying info.
What would be a proper way to use custom properties with a typed view.
E.q. if the view contains 2 fields. If filled, you want to show field 1, else field 2.
Whether this is a TypedView or an Entity, you can create a custom property (better in a partial class/file), and display data from any of the fields based on whatever condition.
Then use this property in dataBinding.