It's often paired with the Demons Bloodletter of Aclazotz and Archfiend of the Dross, two cards that will make the burn damage your opponent feels from Unholy Annex even greater
That's 16 more than Toph, Hardheaded TeacherToph, Hardheaded Teacher or the more mundane Uncle IrohUncle Iroh has in Gruul, 15 more than Sokka, Bold BoomerangerSokka, Bold Boomeranger in Izzet, and 13 more than Guru PathikGuru Pathik and The Lion-TurtleThe Lion-Turtle have in Simic, to say nothing of the multiple single-color Lesson commanders that have access to a fraction of that (return readers will note that I didn't even mention Lessons when I wrote about Gran-GranGran-Gran last week)
Only costing three ink to play, every time this Ursula sings a song, she can essentially sing it twice and then be placed back in the deck rather than discarded
Its a good card in any Swamp-based situation you find yourself in, especially if youre looking to swing in with that Ulamog's Crusher