Speaking of adding to a number, in some dynamic languages, you can add 3/5 to 7/5 and the result will be 2, of type integer, indistinguishable from the object produced by a literal 2. That 3/5 and 7/5 come from some run-time source, so the result type can't be statically hard-coded to integer or rational or whatever. And so now on the static side you're into variant types and "maybes" and other junk creating an incomprehensible soup which basically Greenspuns dynamic typing in a way that will get your name cursed by subsequent maintainers.
I can't make heads or tails of what your criticism is. Algebraic types are wonderful, I find it difficult to code in a language without them. I'd hardly call it 'junk'.
