It's not only a tradition from Catalunya. It's also celebrated in the regions where there are a lot of "castañas" in the Iberian Peninsula, like Galicia, Cantabria, Asturias, etc. And not exclusive to Spain, Portugal also does it. I mean we even brought that tradition to Canary Islands. It's very common to find "Castañeras" in public places all around Spain in Fall.

The only difference is that in Catalunya they also do panellets in Castañada, which is sort of a mazapan. But that's it.

The people that write this articles looks like they don't travel outside Catalonia. Writing that "Castañeras" are exclusive on Catalonia it's quite the sentence. Travel around any place in Spain or Portugal and you will find Castañeras. And they also celebrate Castañada. The only thing that is true is the part of panellets in this article.

Reference.

[–] [email protected] 2 points 2 weeks ago (4 children)

Interesting, I had a look at other articles and they also insisted on Catalunya's origin for the festival

https://historia.nationalgeographic.com.es/foto-del-dia/origenes-castanada-tradicion-catalana_22439

Found this one which gives a broader overview https://elpais.com/gastronomia/el-comidista/2018/10/29/articulo/1540815194_408955.html

Abundante en las zonas de Galicia, Asturias, El Bierzo, Canarias, Extremadura o las sierras de Málaga y Huelva, fue un alimento básico para nuestros antepasados hasta que llegó la patata. Su temporada se extiende de finales de octubre hasta diciembre y es un habitual en la gastronomía del Día de Todos los Santos y diversas festividades como el Magosto en Galicia, el Amagüestu en Asturias o la Castañada en Cataluña. El objetivo de todas es hincharse a castañas y beber vino o sidra dulce, se llamen como se llamen.

The article in the OP probably focused on Catalunya as they are centered on Barcelona