Most generational GCs will work better if you don't reuse objects - reuse extends lifetime and increases probability of promotion to an old generation, slower to scan. (Go's GC is not generational today, AFAIK.) I'd take any recommendations along those lines as last resort techniques to reduce pressure on critical path loops. And a more sophisticated runtime may allocate such temporaries in registers or on the stack.

In other words, you're tuning to today's runtime if you reuse heavily. Those techniques may not age well, and will harm readability and maintainability.