Is Rust's way of handing type promotion too simplistic (i.e. forcing user to always do explicit casts)?

I watched a video on a novel way to deal with type promotion and casting. The relevant part for Rust is starting here. The speaker states earlier that C and C++ are broken in this regard (I tend to agree), so this is not the point. But from just looking at the speaker's example, would you agree that explicit casts in Rust expressions too often become pervasive, defeating its own purpose?

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