No, not at all. It is true that units are erased at runtime, but the compile time behavior is quite sophisticated, going well beyond anything that's possible in C# or OCaml. (Your link is quite interesting, but I think that using a custom build step is "cheating" to some degree in that you can add arbitrary features by adding language-external post build processing).
By being built into the language, units of measure in F# work naturally with type inference (and definitions can be measure-generic), so:
let weirdOperation (x:float<_>) (y:float<_>) = x * x + y * y * y
will be inferred to have type
x:float<'u ^ 3> -> y:float<'u ^ 2> -> float<'u ^ 6>
