Honestly, I think you've nailed it. The key is balance. Pure static does create a lot of extra up front cruft at the expense of long term safety. Pure dynamic

Honestly, I think you've nailed it. The key is balance. Pure static does create a lot of extra up front cruft at the expense of long term safety. Pure dynamic does create a much faster path to features at the expense a lot of long term confusion. The reason we have this conversation is because of web applications where everything is travelling over the wire as a string, consumed by the web server as a string, converted by whatever language the server is in...into something that it can use...9/10 times validated to make sure it reflects what we need and then stuff into a database. In the case that you're using a SQL database, a huge number of people are enforcing types at the database layer and the validation layer. Since so much is "consume and store" followed by "read and return" the types at that server layer end up creating a ton of extra work that in many cases shows little to no benefit. At the point that you're doing more in server layer, suddenly it becomes a lot more useful. At the point you're working on desktop, mobile, embedded, console, computational and graphics...static is going to provided more value. At the point you're working on web in front of a database, the value is much more questionable. This is really one of the reasons I'm such a huge Elixir fan because IMO it strikes that perfect balance where I live...on the server in front of a database. You get static basic types with automatic checking via dialyzer and you can make it stricter as necessary.