Audio Conferencing option

Hi - just wondering the point of the $100 per month audio conferencing options as opposed to the pay-as-you-go option?  It seems like you are paying $100 no matter what, and you still get charged if you go over the usage limits.  Am I missing something or a benefit that I'm not aware of right now?

We have Zoom One Business license and the $100 audio conference add-on currently.