Damn there's a lot of people here complaining about innovation.
Here's a quick tip, if you can think in 10 seconds a problem with this, the engineers that work on these projects for YEARS probably already thought of it.
1 - Yes, wireless isn't 100% reliable, so they are going to need more than one backup system. With a data connection between the trailer and the car, you have MANY ways to alert the driver that there's a problem, AND your trailer has a processor that can safely handle problems. Heck, a VERY easy fix is to just keep a camera pointed at the license plate and keep it centered in the view while flashing a thing on the dashboard that the trailer isn't working correct and you need to pull over. Worst case the trailer detects a problem and slows to a stop with the emergency flashers on, but even that would only be needed if several other options failed.
2 - People bitch all the time about Giant Dually Trucks(tm) that are just used for daily driving. Well, pulling trailers on the weekend is why a lot of people have the excuse for this. If we can eliminate the need for the heavy tow vehicle, then you can just drive a small sedan and still be able to go glamping on the weekends.
3 - There are MILLIONS of travel trailers out there right now. If we switch to small EVs overnight, we can either landfill all those trailers, or figure out a way to retrofit them to still be useful.
4 - Encryption is a thing. If this is using current, modern Wi-Fi, then you can be pretty damn sure that nobody is going to hack into that connection.
Sure, companies cut corners and cheap out of things all the time, but this is absolutely possible to do right, and solves an actual problem.