I really liked her performance and the advert with her in it. I think she is a fabulous dancer, singer and actor.
I was super surprised when Tiffany & Co chose her for a spokes person for their brand. Tiffany to me, is based on classic and elegant designs, and Lady Gaga dresses in very provocative and 'full on' ways. Especially since Lady Gaga was the star in American Horror Story as a Ghost/Vampire creature in Season 6 which doesn't scream Tiffany & Co style to me. When I compare the Lady Gaga advert with the advert they had for the Bow design- there is a huge contrast. There is less of a contrast when compared with the advertising done for the Atlas collection (this could be what they are building upon).
I thought Tiffany might be trying to be more modern and appeal to wider audience. I'm sure their marketing department is more strategic than I am haha.
I like the designs they made for her, alas I haven't seen them in person yet. The style certainly suits Gaga! I'm not 100% sold on purchasing one for myself, but I am not ruling them out fully.