[xKingfisher]

Not to mention the very real risk of accidently invoking the wrong constructor. If you change the type of a vector, push_back is a good deal safer than emplace_back.

Especially since many of the standard containers have many more constructors that you'd think - hello std::vector(size_type count).

[codeflo]

That’s one of my favorites as well. The fact that C++ will so happily auto-convert almost anything into an integer makes it even more likely to hit this accidentally.

[xKingfisher]

And explicit constructors won't save you from this one.

[rq1]

Use Phantom Types. The compiler will help you.