The only big thing (which the article does call out) is that this is about scaling _traditional_ SQL databases. Traditional SQL databases don't have builtin horizontal scaling.
The article is a little hazy about "specialized extensions":
> When we need to store and work with geospatial, time series and other specialized data, we can sometimes use a database extension like TimescaleDb or PostGIS to make the data processing and storage more efficient.
The point I'd call out is that specifically TimescaleDB allows you to horizontally scale PostgreSQL which is a pretty radical improvement on vanilla Postgres.
https://blog.timescale.com/blog/timescaledb-2-0-a-multi-node...