You can't really "optimize" that every function call now has a branch after it to check for an error. That's a design choice Zig made at the cost of performance

You can't really "optimize" that every function call now has a branch after it to check for an error. That's a design choice Zig made at the cost of performance, which is not inherently bad. After all, lots of languages intentionally sacrifice performance for some other benefit. But those types of choices are not things you can just waive a magic wand at later to hope it goes away.