You seem to be confusing the Duration type with Duration values. Yes, if you insist on using a typed value, instead of an untyped constant, then that value needs to be type Duration.
But Duration(1) is way different than time.Second. honestly it just sounds like you don't know the language, and aren't willing to learn it. Go is not Rust. Things are different, that doesn't mean Go sucks.
The entire purpose of the distinction that I’m remarking on is that Duration * Duration → Duration is mathematically utterly incorrect, and especially super misleading when the base quantity for the unit is nanoseconds rather than seconds, yet that is what Go requires, beyond constants, which it special-cases. To be sure, with durations, the distinction doesn’t matter much because arithmetic performed is with constants, and that’s why I say that Go is probably still better with this wonky unit scheme than with entirely unitless quantities, but there are plenty of situations where you will want to multiply durations by typed numbers, and so you’re forced to do the mathematically-ridiculous `Duration(n) * duration` rather than `n * duration`.
You’re looking at this from the application perspective, where with the specific example of durations constant multiplication is certainly far, far more common. But you’re discounting library concerns, where it would not be out of the ordinary to receive a time.Duration and an int64 from parameters or a struct or similar.
This is also pretty typical of the trade-offs Go makes: it focuses on making things nice for the application writer, mostly pretty successfully, but at the regular cost of pain and with serious typing compromises for the library writer.
But Duration(1) is way different than time.Second. honestly it just sounds like you don't know the language, and aren't willing to learn it. Go is not Rust. Things are different, that doesn't mean Go sucks.