How can interdental brushes actually replace floss?

Hi all! I just had an appointment with my dentist, where I told him that floss tends to get stuck between many of my teeth. He reckoned that it could be because of poor quality fillings and/or cavities that he saw between some of my teeth, and said that it would probably be better if I switched to interdental brushes. I did some research on them online, but found that those only really clean one specific part of the tooth, meanwhile a floss can slide along the entire length of it, and even go beneath the gumline. So how can interdental brushes really be a full replacement? Opinions online seem differed, so I'd appreciate an in-depth explanation. Thank you!