After an exchange here (and fra answering that very question as well) the Pebble support team explicitly wrote this in a mail: -- So Usage Logs send step coun

After an exchange here (and fra answering that very question as well) the Pebble support team explicitly wrote this in a mail: -- So Usage Logs send step count, and sleep count, to Pebble's servers. Usage Logs are also necessary for Voice responses. The voice is sent to our voice service, transcribed and sent back (this voice data is not stored at any point). You can use the Pebble Health app with the Usage Logs switch off and your data will not be sent to Pebble's servers. You can also sync that data to either Google Fit or Apple Health if you choose while still keeping the Usage Logs switched off. -- In other words: 'Usage logs' seems to be the all-in-one switch that sends the data to the cloud, everything Peble Health related should work if you disable that. Ignoring the limitation mentioned: You won't be able to use voice replies. So I'd say that the Pebble is a really decent choice for a privacy concerned person. On that note: I certainly hope that Alexa can be disabled on the Pebble Core..