Is there a specific reason that TZ support is not provided?

I might be missing something, but in my experience, (1) it can be informative to have the TZ information, regardless of the ability to compensate for time zone differences; (2) too many programmers either don't know how to correct for TZ correct -- especially with DST -- or they don't even try due to ignorance or laziness. Many of the problems I've had (with client databases) have been resolved by identifying code that forgot how to do things like this.

I recognize sqlite's DATETIME is also without TZ, but that doesn't make it the best way to go.

I suggest a way forward:

• add support TIMESTAMP WITHOUT TIME ZONE and TIMESTAMP WITH TIME ZONE
• TIMESTAMP is just an alias to "without"