First of all, great report. "Ezviz offers basic IFTTT arm/disarm integration, but does not integrate video.", how so? thought EZviz is all about video themselves? no?
Hikvision Ezviz Mini Trooper Totally Wireless Camera Tested
That should read that they don't integrated their video with third party services currently. With Arlo, you can see live and event video in the SmartThings app, for example. You can't do that with Ezviz.
The IFTTT integration allows you to trigger actions based on alarms on Ezviz cameras and to toggle privacy mode or sleep mode or alarm notifications based on other triggers. I've tested both and they work fine, it's just more limited than fully integrating to smarthome systems and displaying video.
I would not use Wi-Fi for any critical applications, at least not on 2.4 GHz as of today, since this frequency band is totally overcrowded today and very poor throughput (where I live anyway) and almost impossible to use with reliability.
Of course I use Wi-Fi, but for non-critical applications, and I try to only use 5 GHz, since 5 GHz has 23 non-overlapping channels in comparison of 2.4 GHz who only have 3 non-overlapping.
And, cables for all critical applications.
How was the ease of setup? I had so much problem getting it up and running and it kept disconnecting once placed outside even though the base station was close to the camera.
Setup was straight forward following the directions, and worked without issue for us. Since the camera needs to scan the base station QR code during setup the devices were within a couple of feet of each other. The camera dropped once during testing at ~80'.
What about ONVIF conformance or compatibility with other VMS platforms? We're always running into situations where we could use a camera like this. I don't think I would use it for outdoor or commercial applications. I could use this inside houses all day long. Right now we hardwire all outside cameras, most people don't want fixed or permanent cameras inside, they want to move them around. We use wifi right now but people hate wires and complain that it's not really wireless.
U3 - This camera is not ONVIF conformant nor does it integrate with NVRs/VMS platforms.
The use case you described is actually how my home system is setup. I have "brand x" cameras on the outside of my house that write to an NVR, and we have an indoor wireless (wired power) camera that just records to an SD card. I can view them all through the same app. We have 4 young kids and use the wireless camera as a nanny cam / baby monitor. As you said - moving that one around as needed.
This could be accomplished with Hikvision gear (or OEM) and the Trooper, as we showed a 2042 alongside the Trooper during live view in the images above.
Update: After only a couple hours of this mounted outside I had to turn the motion alerts off. There are no sensitivity settings, which means any time the wind blew my porch shade a little, it triggered. Car went down the street 30-40' away? Triggered. Person on sidewalk way past where I wanted to detect? Triggered.
Tomorrow morning I'm going to re-aim and see if these problems continue.