Is using 'new Function' in javascript as an inner function (within closure) considered a bad practice?

Question

When I read about curry function, I think it's hard to create a recursion for building nested function. Then I take a look at ramda's implementation, it's true that to create an curried function with arbitrary number of arguments. Then, why not building it with string like this:

function curry(fn, arity) {
  arity = typeof arity === 'undefined' ? fn.length : arity

  if (arity < 1) {
    return fn
  }

  function build(n, space = 2, args = []) {
    if (n < 1) {
      args = args.map(arg => 'a' + arg)
      return `fn(${args.join(', ')})`
    } else {
      return `function (a${n}) {\n${' '.repeat(space)}` +
        `return ${build(n - 1, space + 2, args.concat(n))}\n` +
        `${' '.repeat(space - 2)}}`
    }
  }
  const curryCreator = new Function('fn', 'return ' + build(arity))
  return curryCreator(fn)
}

It can be used like this:

function sum5(a, b, c, d, e) {
  return a + b + c + d + e
}

const sum = curry(sum5)

Which will produce this:

function (a5) {
  return function (a4) {
    return function (a3) {
      return function (a2) {
        return function (a1) {
          return fn(a5, a4, a3, a2, a1)
        }
      }
    }
  }
}

How bad it can be to use new Function for this functionality?

The use case is just to generate a function and argument placeholder like in the example above. My question is more specific than this which addresses the generic use case of eval or new Function. As you can see in my example, it's a private function which is won't be called in another place.