Besides the particular trait of being nice, there’s not much information about firmware 3.69 yet, or why it got released just now. The previous firmware update, 3.68, was released 5 months ago by Sony, and it was pretty much everyone’s expectation that we wouldn’t see significant firmware updates for the Playstation Vita moving forward.
Firmware 3.68 is vulnerable to h-encore, a full exploit on the PS Vita. There’s a possibility, although it’s not been confirmed, that 3.69 patches the exploit. Alternatively, it could be an unrelated patch to close some Vita related services on the PSN, just like we’ve seen a few years ago with an unexpected PSP update.
At the time of writing, Sony’s official site still says the latest firmware is 3.68.
As always, if you use a hacked console (or want to hack it at some point), we advise not to update, until details surface on what firmware 3.69 actually brings to the table.