# [Charcoal], 10 bytes

    ＦＡＦι⊞υιＩ‽υ

[Try it online!][TIO-lm345kyi] Link is to verbose version of code. Explanation:

    ＦＡ

Loop over the input numbers.

    Ｆι⊞υι

Push each number that many times to the predefined empty list.

    Ｉ‽υ

Output a random number from that list.

8 bytes using the newer version of Charcoal on ATO:

    Ｉ‽ΣＥＡＥιι

[Attempt This Online!][ATO-lm345kyi] Link is to verbose version of code. Explanation:

        Ａ       Input list
       Ｅ        Map over elements
          ι     Current element
         Ｅ      Map over implicit range
           ι    Outer element
      Σ         Flatten
     ‽          Random element
    Ｉ           Cast to string
                Implicitly print

A port of @Arnauld's JavaScript answer in straight succinct Charcoal is only 6 bytes:

    Ｉ⌈∨Φθ‽

[Try it online!][TIO-lm3yuzbp] Explanation:

        θ   Input list
       Φ    Filtered by
         ‽  Random coin flip
      ∨     If empty then implicitly use input list
     ⌈      Take the maximum
    Ｉ       Cast to string
            Implicitly print

[Charcoal]: https://github.com/somebody1234/Charcoal
[TIO-lm345kyi]: https://tio.run/##S85ILErOT8z5/z8tv0hBwzOvoLREQ1NTAczL1FQIKC3O0CjVUcjUtOYKKMrMK9FwTiwu0QhKzEvJz9Uo1dTUtP7/PzraUEfBSEfBWEfBJDb2v25ZDgA "Charcoal – Try It Online"
[ATO-lm345kyi]: https://ato.pxeger.com/run?1=m70iOSOxKDk_MWfBgqWlJWm6FjeNAooy80o0nBOLSzSCEvNS8nM1gktzNXwTCzQ88wpKSzQ0dRRAnEwdhUxNMLBeUpyUXAzVvzxaSbcsRyl2XXS0oY6CkY6CsY6CSWwsRBIA "Charcoal – Attempt This Online"
[TIO-lm3yuzbp]: https://tio.run/##ASoA1f9jaGFyY29hbP//77yp4oyI4oiozqbOuOKAvf//W1sxLCAyLCAzLCA0XV0 "Charcoal – Try It Online"