I might be wrong but as I've understood it Builder Pattern is mostly used as a solution to mitigate mutable state from being accidentally shared. Which is duct

I might be wrong but as I've understood it Builder Pattern is mostly used as a solution to mitigate mutable state from being accidentally shared. Which is duct taping around the complexity instead of removing it. In Swift the copy on write happens as an implementation detail: https://stackoverflow.com/questions/43486408/does-swift-copy-on-write-for-all-structs https://stackoverflow.com/questions/43486408/does-swift-copy... I don't really know why but the coding patterns (what I call culture) that are popular for each language are very, very different even when they can support the same feature-set.