Need advice

If I try to get Nanami Startrail, is it worth it to have her only at S rank? Because I’d like to use Dante and Vergil as effectively as possible, but I have doubts about whether it’s worth it, since I created my account just a few days ago and I have 12500 BC. Honestly, I’m a bit scared to spend and then end up with few tickets when the collab arrives, since I’d like to have 46000 BC to be able to get everything (Dante, Vergil, sig weapon, cub).