Depends. Personally I\'m going for Elena because I have enough exploration and attempt cards she\'s probably only going to cost me 300 diamonds. But like any angel (except for tourney angels and theia) they\'ll eventually be attainable.
If you don\'t have a 100% hit angel you may want to get her. If you do she could possibly replace your main or make a good buff. Getting her counts towards unbreakable and covenants. But if you have angels to spare and dont really need another one the lvl 11 fuse gem is really nice. But I think the benefits of getting an angel like Elena is really good. Since now they are more than just for show with angel artifacts and unbreakable bond. Gives more BR than a fuse gem in the end.