Does smart have unlimited internet?

Excuse me, could you clarify something for me regarding the capabilities of smart devices? I've heard some claims that certain smart devices offer unlimited internet access, but I'm wondering if this applies universally to all smart devices. Specifically, I'm interested in knowing if the term "smart" inherently implies that these devices come with unlimited internet connectivity, or if this is a feature that varies depending on the device and its service plan. Can you help me understand this better?