White noise machine v. app

As

I use the white noise app on an old cell phone. I just purchased the Taking Cara Babies e-book for 3-4months and it recommends getting a separate white noise machine citing that it is better than apps. For anyone that has done both, was there a difference in your child’s sleep? I know the machines are not that expensive so it’s not about trying to save a dollar, but do i really need one more apparatus?

Thanks in advance for your feedback!