Question about baby items-should we get our 4 month old an exersaucer?

She already has the Rainforest Bouncer, the Rainforest Jumperoo, an infant to toddler rocker and a walker with toys. She also has 2 play gyms and numerous toys. Several people have told me that we need to get her an exersaucer and I'm just trying to figure out if it will just sit there.