I wouldn't suggest you get one, as it is probably way too expensive and you want significant confirmation it really works, as advertised.
It is theoretically possible that it does work as described. But they may not be telling the full story. I.e. missing out on inaccuracies with it, how often it gets things wrong and it may not be trained up in enough devices to be truly useful.
I think you would be better off, using kill-o-watt meters, and common-sense/knowledge, on how much electricity common devices use.
E.g. Things which produce huge amounts of heat, usually use lots and lots of electricity.
Instruction manuals sometimes tell you how much electricity something uses. E.g. A TV.