What's the point of unary plus operator in Ruby?

Apart from making a nice symmetry with unary minus, why is unary plus operator defined on Numeric class? Is there some practical value in it, except for causing confusion allowing writing things like ++i (which, unlike most non-Rubyists would think, doesn't increment i).

I can think of scenario where defining unary plus on a custom class could be useful (say if you're creating some sexy DSL), so being able to define it is ok, but why is it already defined on Ruby numbers?