I've been using LendUp regularly just in an attempt to help rebuild my credit (I've never actually needed the loan). I think their service is fantastic and I really hope they remain independent and true to their mission as they grow.
This is a horrible way to build credit. You are literally throwing money in the trash. Go get a secured credit card.
Diversity of types of loan is worth it (card, installment debt). If you're borrowing $1000 at 7% for a year it's on par with the fees for a secured credit card.