It's not always advertisements. Sometimes, the company will hire some oxygen waster that wants to boost "engagement" in order to justify their job and salary, so now your system is using your telemetry data to find ways to waste your time (as well as track whether they've indeed managed to waste it) even though advertisements themselves aren't (yet) involved.
Not to mention, advertisements don't have to be served over the same device that collects the data. The inverter company can very well collect the data, sell it to a data broker where other ad companies will use this data.