SPM01 - compact clamp energy monitoring - why can't it be used downstream by devices?

Hardware
1

I am looking at monitoring some of the more power hungry appliances in the house to know if they are on or off.
Like a big aircon and clothes dryer (220v ).

I also really prefer the solution to be inside the outlet box (we use the Gewiss system here).

After reading a few posts on Reddit of fires with relays that do passthrough energy monitoring I figured those are not an option for these power hungry motors (inductive load power spikes and all). So the best option seem to be the clamp meters.

The smallest one I could find on AliExpress are the SPM01 from Bituo-Technik Wifi/ZigBee IoT Energy Sensors - SPM01 (1P+N, 63A)| Bituo - data sheet there. It’s not cheap…

Whats strange is the data sheet explicitly says you should not use it downstream by devices (my use case):
“SPM01 can be damaged, if it is installed downstream of switching devices – such as a contactor, frequency
converter or motor starters.”

Any electricians here can tell me why is that or maybe I misunderstood the sentence?

2

I know this is old, but I beleive they are talking about installing it downstream of controllers that vary voltage or use PWM etc, such would be used to drive motors etc.