Extra security ?
A little bit. HTTPS just encrypts data as it travels between your computer and the TSP server. So this at least adds a little protection for your password, if you're logging on via public Wi-Fi where somebody might be snooping on you. But the server itself isn't any more secure than it was.
One problem we will not solve: your browser will give you a security warning for most pages, because any hotlinked images from other sites are likely to be HTTP instead of HTTPS. This applies to many members' avatars, images in their signature lines, and images that they've linked in their posts. There's no way to avoid this on a public forum, so these warnings will persist. (I'm going to try to fix it at least for the forum homepage, where the admins have control over all the displayed images.)