Reasons.

Why it's good to not have a favourite member.
- You don't have to decide.
- You can choose to buy fan-goods of members which looks good nya, instead of die-die only buy the goods of that member you like nya.
- You have 13 awesome members.

Why it's NOT good to not have a favourite member.
- Most fan-goods of different members, majority are always nicer looking so you ended up buying more as compared to if you have only ONE favourite member.
- Every single member's business is YOUR business.

But because you love them all, so it's ok!! (^^ )