Disable alpha versions in your Curse client if you do not want multiple updates per day. Make sure you check main download preference as well as DBM's individual download preference. You could have primary method set to release and dbm still set to alpha. Right click on DBM itself in curse client addon list and set it to release/beta to avoid the daily updates.
Some addons are standalone, and are able to run without any additional addons being installed; others can require certain other addons to be installed to work at all, or integrate with other addons to provide additional functionality. Collections of addons that have been put together to form a coherent user interface are sometimes referred to as UIs.
Since it's like a premium version and it's not modifying game files it gets by somehow. I personally hate Zygor's guides and always have, it's just personal honestly. I understand some people like his guides and have no problem paying for them but I personally hate the idea of charging someone for an addon that - as this post points out - has plenty of bugs in it. These were fixed last week and if I'm paying cash for an addon I want that addon bug free and not causing a hassle and taking my time away when I could be doing a better job without an addon at all.
I only subscribed about 2 days ago after coming back to WoW after 6 years. The game has changed so much since I left right around the Cata release. I decided to start fresh on a new server. I still had all my old links and logins to places like Curse, WowInterface, etc. Loaded up all the addons I had favorited years ago (of the maybe 1/3rd that were still maintained). Got to level 20 in a few hours of playing. Had to look a bunch of stuff up.