Not sure on uncapped providers. But in retail or temp locations you have a huge market of cradle point devices. Meraki is no able to take that market. Between 67/68c and the new Z device you can stand up remote offices in a few clicks.
The built in LTE offering increased reliability over usb, and better speeds can be used to replace some point to point dedicated connections (MPLS). Meraki seems to be pushing SD-WAN a lot. If I am in a rural are that getting connectivity is a issue I can quickly deploy one of these devices and have a connection. If you out way the cost of dedicated connections for MPLS having 2 connections on a mx even if one is cell and SD Wan you can net some savings.
Unless you are in a big metropolitan area with multiple providers good luck finding one without caps.