The launcher doesn't automatically update no. When you run the launcher it shows you the last time you updated and the last time of update, you still have to update/install.
The new launcher provides you with the ability to update Test/Live/Beta/EMU all from one interface as well as gives you access to update any paid plugins or watched macros from the very same interface. It's a QoL improvement but the idea wasn't to have it always monitoring and still allow the user the freedom to update selectively in the event they weren't ready to update yet. Sometimes VV patches but the patch isn't mandatory, hence the optional update.
When you require the update is when EQ patches and parts of the internals must be changed to fix all the bits and bobs that make it function correctly. In the case of the mq2chatwnd plugin, the update does correct that issue, however the update isn't required for mq2 to function without crashing. So it's not going to give you a date warning if you don't patch.
Hope this clears things up.