My concern is - can it still work with power provided by a regular USB socket on the TV? The specs claim it needs a 1 amp power supply, and most sockets can't do that much.
Maybe the specs overstate it.
I've used the old chromecast successfully like this. The manual also suggested to do it. One downside was that this means the chromecast can no longer turn your TV on due to lack of power. When casting to it, it will turn on my TV and switch it to the chromecast input which is quite nice.
Wait, it can do this? I had no idea. Freaking awesome.
On the last iteration, my Chromecast would only connect to my WiFi about 2/3 times after reboot which hopefully is better with the new WiFi since the hassle was enough that I gave it up for an AppleTV. I bought 2 Chromecasts the first day they were announced and evangelized a fair bit to my friends and family but they ended up not being as useful as I had hoped.
The marketing copy for the new Chromecast mentions that it, too ships with a 5V power supply (1A this time around) for powering the Chromecast.
I'd be shocked to see a TV or >~£120 monitor without MHL nowadays, but perhaps it really is the case...
Not widely supported, but it's basically power-over-HDMI among other things.