I'm hoping that we provide ergonomic alternatives for all the individual use cases. The brevity of `as` is a major reason we haven't removed it yet.
We have `.into()` for lossless conversions like u32 to u64.
We need to fix the fact that `usize` doesn't participate in lossless conversions (e.g. even on 64-bit you can't convert `usize` to `u64` via `.into()`).
We need to fix the fact that you can't write `.into::<u64>()` to disambiguate types.
And I'm hoping we add `.trunc()` for lossy conversion.
And eventually, after we provide alternatives for all of those and some others, we've talked about changing `as` to be shorthand for `.into()`.
