If you have an unlimited plan on an iphone does cellular data matter?

Does cellular data really matter as to how high it is if you have an unlimited plan for your iphone?

If you have an unlimited data plan, then no, how much data you use does not matter.

If your plan allows for unlimited data, then no, cellular data doesn't matter. But few plans offer unlimited data. Even if there's no cap on data, the contract might say that Internet speed will be dramatically slowed if you use more than a certain amount of data in a billing cycle.