The way I see it, the standard is should be taken as a bare minimum requirement. Ideally standards compliant SQL would work on any RDBMS, though I don't think that ideal has ever been realized. Supplementing the standard with extensions when the standard happens to have ergonomic problems seems to do more good than harm. IMHO writing SQL with the extensions of postgres or sqlite is a lot more enjoyable, which I think counts for a lot.
There's room for argument there. From my perspective, as someone who's had to spend a lot of time maintaining databases, I would rather have just one way of doing it, even if the one way of doing it that I get stuck with is not the way I would have picked if I had had my druthers.
The problem with TMTOWTDI is that it means there's also more than one way to have to understand and reason about. Which ultimately makes my job harder.
