UIView is similar to CALayer in QuartzCode. The only difference is how the code is generated. CALayer generates core animation code while UIView generates UIView block based animation code. You can even change between these two types in QuartzCode in Inspector Panel. When the type is changed to CALayer or UIView, generated code will be appropriately changed.
When the type changed, equivalent animation keypaths will also be changed accordingly. CALayer position keypath is equivalent to UIView center keypath. CALayer opacity keypath is equivalent to UIView alpha keypath. Other keypaths that are not supported will be automatically removed.
UIView is included in QuartzCode to help developers experiment and get UIVIew block based animations easily. Recommended way to get UIView code is by using selection copy with CMD +C. UIView is not intended to be used with other layer type because the generated code may seems awkward. Please keep this in mind if you use it with other layer type.