Collecting usage statistics is quite common for apps, but in Maemo/MeeGo/Sailfish land the rules are a bit different.
And we're proud of that.

It's good that you're honest with your intentions, and that it raised the security concerns about the Sailfish platform in general.

But always let the user decide if they want to opt-in to help you improve the product. The comments in the store are a valuable source of feedback, too. So collecting usage statistics may not even be needed.