It was some special kind of exclusive bonus chest thingy, it wasn't as bad as he points it, it was like a bonus thingy you could ignore them. I honestly didn't care for it at all.

I think it was similar to the mini game ships thing on Black Flag, but on your phone and sending assassins instead of ships and maybe solving some puzzles, can't remember.

It made more sense as a phone app, because it was like on Black Flag you sent stuff and that would take x time and then you would get the results, so in a phone you would easily check the progress and maybe get a notification, instead of having to enter the game to check just that.

EDIT: It seems Black Flag also used an app, I played later and now it's a thing in-game I guessed that was the original version honestly.