It’s the traditional way of wearing a chotki which makes us think it is one. As someone else has said, he was the Ordinary for Eastern Catholics in Argentina before his election as Pope of Rome.
I suppose there may be people who wear rosaries like that, but I’ve never seen it.
Cdl. Arinze, and Cdl. Ratzinger before him, have both categorically stated that the rosary should not be worn except as part of a holy habit for consecrated religious (and novices in same communities).
As to the distinction:
A prayer rope is a rope, string, or chain with knots or beads upon which to count prayers. It’s used to both count the prayers without needing to keep count, and to remind which prayers go when.
The Chotki is a Slavic Byzantine prayer rope, usually knotted, of any of a number of lengths. Faithful of these churches may be blessed by their pastor and/or spiritual father to wear the chotki on the wrist. Near identical ones are used with different names in the Greco-Byzantine and Syro-Byzantine traditions, as well as the Ethiopian, but those also tend to allow beads more readily. The chotki is normally used for chanting the Jesus Prayer.
The Lestovka is another Slavic Byzantine prayer rope, but noted for being made of leather with wood “rungs” - inspired by “The Ladder of Divine Ascent” - with specific groupings as specific commemorations.
The Rosary is the Prayer Rope and its specific rule of prayer popularized by the Dominican Friars. It’s a codification of a cluster of similar prayer rules from the west into a singular devotional praxis. It’s been modified by the Papacy since institution within the Dominican Order as a formal part of their constitutions.
The “Servite Rosary”, also called the “Seven Dolor Rosary” and the “Dolor Beads”, is another western prayer rope, with a different prayer rule.
prayerbedes.com/?page_id=35 has an example of the Servite Rosary as used by some Carmelites.
