I mean - I agree for the typical multi-user, SaaS webapp. But I don't think that's what these folks are proposing. If they are - yeesh, count me out.
If on the other hand they're talking about single-user, software in the small - hell yeah. In fact, I'd also promote DuckDB in this regard (mostly for analytics) - with the power of a single machine these days, you can do a surprising amount and never have to worry about distribution. Unless you know you'll have to, in which case you're probably just digging yourself a hole?
The reason the parent post is complaining that it doesn't make sense, is because people have indeed pushed the idea of using SQLite as an alternative for web apps like that.
The typical multi-user SaaS webapp doesn't have anywhere near enough users to overwhelm a single SQLite instance. Of the few that do succeed to the point where that's no longer true, a significant fraction can use techniques like sharding to stretch SQLite further.